Hydrogen peroxide

Last updated


Hydrogen peroxide
Ball stick model of the hydrogen peroxide molecule
Structural formula of hydrogen peroxide Wasserstoffperoxid.svg
Structural formula of hydrogen peroxide
space filling model of the hydrogen peroxide molecule Hydrogen-peroxide-3D-vdW.png
space filling model of the hydrogen peroxide molecule
IUPAC name
Hydrogen peroxide
Other names
Perhydroxic acid
Dihydrogen dioxide
Oxygenated water
3D model (JSmol)
ECHA InfoCard 100.028.878 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 231-765-0
PubChem CID
RTECS number
  • MX0900000 (>90% soln.)
    MX0887000 (>30% soln.)
UN number 2015 (>60% soln.)
2014 (20–60% soln.)
2984 (8–20% soln.)
  • InChI=1S/H2O2/c1-2/h1-2H Yes check.svgY
  • InChI=1/H2O2/c1-2/h1-2H
  • OO
Molar mass 34.0147 g/mol
AppearanceVery light blue liquid
Odor slightly sharp
Density 1.11 g/cm3 (20 °C, 30% (w/w) solution) [1]
1.450 g/cm3 (20 °C, pure)
Melting point −0.43 °C (31.23 °F; 272.72 K)
Boiling point 150.2 °C (302.4 °F; 423.3 K) (decomposes)
Solubility soluble in ether, alcohol
insoluble in petroleum ether
log P -0.43 [2]
Vapor pressure 5 mmHg (30 °C) [3]
Acidity (pKa)11.75
−17.7·10−6 cm3/mol
Viscosity 1.245 cP (20 °C)
2.26  D
1.267 J/(g·K) (gas)
2.619 J/(g·K) (liquid)
−187.80 kJ/mol
A01AB02 ( WHO ) D08AX01 ( WHO ), D11AX25 ( WHO ), S02AA06 ( WHO )
GHS labelling:
GHS-pictogram-rondflam.svg GHS-pictogram-acid.svg GHS-pictogram-exclam.svg
H271, H302, H314, H332, H335, H412
P280, P305+P351+P338, P310
NFPA 704 (fire diamond)
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
1518 mg/kg[ citation needed ]
2000 mg/kg (oral, mouse) [4]
1418 ppm (rat, 4 hr) [4]
227 ppm (mouse) [4]
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 1 ppm (1.4 mg/m3) [3]
REL (Recommended)
TWA 1 ppm (1.4 mg/m3) [3]
IDLH (Immediate danger)
75 ppm [3]
Safety data sheet (SDS) ICSC 0164 (>60% soln.)
Related compounds
Related compounds
Hydrogen disulfide
Dioxygen difluoride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Yes check.svgY  verify  (what is  Yes check.svgYX mark.svgN ?)

Hydrogen peroxide is a chemical compound with the formula H 2 O 2. In its pure form, it is a very pale blue [5] liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%–6% by weight) in water for consumer use, and in higher concentrations for industrial use. Concentrated hydrogen peroxide, or "high-test peroxide", decomposes explosively when heated and has been used as a propellant in rocketry. [6]

Hydrogen peroxide is a reactive oxygen species and the simplest peroxide, a compound having an oxygen–oxygen single bond. It decomposes slowly into water and elemental oxygen when exposed to light, and rapidly in the presence of organic or reactive compounds. It is typically stored with a stabilizer in a weakly acidic solution in a dark bottle to block light. Hydrogen peroxide is found in biological systems including the human body. Enzymes that use or decompose hydrogen peroxide are classified as peroxidases.


The boiling point of H2O2 has been extrapolated as being 150.2 °C (302.4 °F), approximately 50 °C (90 °F) higher than water. In practice, hydrogen peroxide will undergo potentially explosive thermal decomposition if heated to this temperature. It may be safely distilled at lower temperatures under reduced pressure. [7]


H2O2 gas structure.svg
Structure and dimensions of H2O2 in the gas phase
H2O2 solid structure.svg
Structure and dimensions of H2O2 in the solid (crystalline) phase

Hydrogen peroxide (H2O2) is a nonplanar molecule with (twisted) C2 symmetry; this was first shown by Paul-Antoine Giguère in 1950 using infrared spectroscopy. [8] [9] Although the O−O bond is a single bond, the molecule has a relatively high rotational barrier of 386  cm−1 (4.62  kJ/mol) for rotation between enantiomers via the trans configuration, and 2460 cm−1 (29.4 kJ/mol) via the cis configuration. [10] These barriers are proposed to be due to repulsion between the lone pairs of the adjacent oxygen atoms and dipolar effects between the two O–H bonds. For comparison, the rotational barrier for ethane is 1040 cm−1 (12.4 kJ/mol).

The approximately 100° dihedral angle between the two O–H bonds makes the molecule chiral. It is the smallest and simplest molecule to exhibit enantiomerism. It has been proposed that the enantiospecific interactions of one rather than the other may have led to amplification of one enantiomeric form of ribonucleic acids and therefore an origin of homochirality in an RNA world. [11]

The molecular structures of gaseous and crystalline H2O2 are significantly different. This difference is attributed to the effects of hydrogen bonding, which is absent in the gaseous state. [12] Crystals of H2O2 are tetragonal with the space group D4
or P41212. [13]

Aqueous solutions

In aqueous solutions, hydrogen peroxide differs from the pure substance due to the effects of hydrogen bonding between water and hydrogen peroxide molecules. Hydrogen peroxide and water form a eutectic mixture, exhibiting freezing-point depression down as low as -56 °C; pure water has a freezing point of 0 °C and pure hydrogen peroxide of -0.43 °C. The boiling point of the same mixtures is also depressed in relation with the mean of both boiling points (125.1 °C). It occurs at 114 °C. This boiling point is 14 °C greater than that of pure water and 36.2 °C less than that of pure hydrogen peroxide. [14]

  • Phase diagram of
H2O2 and water: Area above blue line is liquid. Dotted lines separate solid-liquid phases from solid-solid phases. Phase diagram hydrogen peroxide water.svg
    Phase diagram of H2O2 and water: Area above blue line is liquid. Dotted lines separate solid–liquid phases from solid–solid phases.
  • Density of aqueous solution of H2O2
    H2O2 (w/w)Density
  • Comparison with analogues

    Hydrogen peroxide has several structural analogues with HmX−XHn bonding arrangements (water also shown for comparison). It has the highest (theoretical) boiling point of this series (X = O, S, N, P). Its melting point is also fairly high, being comparable to that of hydrazine and water, with only hydroxylamine crystallising significantly more readily, indicative of particularly strong hydrogen bonding. Diphosphane and hydrogen disulfide exhibit only weak hydrogen bonding and have little chemical similarity to hydrogen peroxide. Structurally, the analogues all adopt similar skewed structures, due to repulsion between adjacent lone pairs.

    Properties of H2O2 and its analogues
    Values marked * are extrapolated
    NameFormula Molar mass
    point (°C)
    point (°C)
    Water HOH18.020.0099.98
    Hydrogen peroxideHOOH34.01−0.43150.2*
    Hydrogen disulfide HSSH66.15−89.670.7
    Hydrazine H2NNH232.052114
    Hydroxylamine NH2OH33.033358*
    Diphosphane H2PPH265.98−9963.5*


    Alexander von Humboldt is sometimes said to have been the first to report the first synthetic peroxide, barium peroxide, in 1799 as a by-product of his attempts to decompose air, although this is disputed due to von Humboldt's ambiguous wording. [15] Nineteen years later Louis Jacques Thénard recognized that this compound could be used for the preparation of a previously unknown compound, which he described as eau oxygénée ("oxygenated water") – subsequently known as hydrogen peroxide. [16] [17] [18] Today, the term "oxygenated water" may appear on retail packaging referring to mixtures containing either water and hydrogen peroxide or water and dissolved oxygen. This could cause personal injury if the difference is not properly understood by the user. [19]

    An improved version of Thénard's process used hydrochloric acid, followed by addition of sulfuric acid to precipitate the barium sulfate byproduct. This process was used from the end of the 19th century until the middle of the 20th century. [20]

    The bleaching effect of peroxides and their salts on natural dyes had been known since Thénard's experiments in the 1820s, but early attempts of industrial production of peroxides failed. The first plant producing hydrogen peroxide was built in 1873 in Berlin. The discovery of the synthesis of hydrogen peroxide by electrolysis with sulfuric acid introduced the more efficient electrochemical method. It was first commercialized in 1908 in Weißenstein, Carinthia, Austria. The anthraquinone process, which is still used, was developed during the 1930s by the German chemical manufacturer IG Farben in Ludwigshafen. The increased demand and improvements in the synthesis methods resulted in the rise of the annual production of hydrogen peroxide from 35,000 tonnes in 1950, to over 100,000 tonnes in 1960, to 300,000 tonnes by 1970; by 1998 it reached 2.7 million tonnes. [21]

    Early attempts failed to produce neat hydrogen peroxide. Anhydrous hydrogen peroxide was first obtained by vacuum distillation. [22]

    Determination of the molecular structure of hydrogen peroxide proved to be very difficult. In 1892, the Italian physical chemist Giacomo Carrara (1864–1925) determined its molecular mass by freezing-point depression, which confirmed that its molecular formula is H2O2. [23] H2O=O seemed to be just as possible as the modern structure, and as late as in the middle of the 20th century at least half a dozen hypothetical isomeric variants of two main options seemed to be consistent with the available evidence. [24] In 1934, the English mathematical physicist William Penney and the Scottish physicist Gordon Sutherland proposed a molecular structure for hydrogen peroxide that was very similar to the presently accepted one. [25] [26]

    Previously, hydrogen peroxide was prepared industrially by hydrolysis of ammonium persulfate:

    which was itself obtained by the electrolysis of a solution of ammonium bisulfate ([NH4]HSO4) in sulfuric acid: [27]


    Catalytic cycle for the anthraquinone process to produce hydrogen peroxide: an anthraquinone (right) is reduced using hydrogen to produce the corresponding anthrahydroquinone (left). This is oxidized using oxygen to produce hydrogen peroxide and recover anthraquinone. Riedl-Pfleiderer process.svg
    Catalytic cycle for the anthraquinone process to produce hydrogen peroxide: an anthraquinone (right) is reduced using hydrogen to produce the corresponding anthrahydroquinone (left). This is oxidized using oxygen to produce hydrogen peroxide and recover anthraquinone.

    Today, hydrogen peroxide is manufactured almost exclusively by the anthraquinone process, which was originally developed by BASF in 1939. It begins with the reduction of an anthraquinone (such as 2-ethylanthraquinone or the 2-amyl derivative) to the corresponding anthrahydroquinone, typically by hydrogenation on a palladium catalyst. In the presence of oxygen, the anthrahydroquinone then undergoes autoxidation: the labile hydrogen atoms of the hydroxy groups transfer to the oxygen molecule, to give hydrogen peroxide and regenerating the anthraquinone. Most commercial processes achieve oxidation by bubbling compressed air through a solution of the anthrahydroquinone, with the hydrogen peroxide then extracted from the solution and the anthraquinone recycled back for successive cycles of hydrogenation and oxidation. [28] [29]

    The net reaction for the anthraquinone-catalyzed process is : [28]

    H2 + O2 → H2O2

    The economics of the process depend heavily on effective recycling of the extraction solvents, the hydrogenation catalyst and the expensive quinone.

    ISO tank container for hydrogen peroxide transportation Container JOTU501003 9.jpg
    ISO tank container for hydrogen peroxide transportation
    A tank car designed for transporting hydrogen peroxide by rail HydrogenPeroxideTankCarBoltonON.jpg
    A tank car designed for transporting hydrogen peroxide by rail

    Other sources

    Small, but detectable, amounts of hydrogen peroxide can be formed by several methods. Small amounts are formed by electrolysis of dilute acid around the cathode where hydrogen evolves if oxygen is bubbled around it. It is also produced by exposing water to ultraviolet rays from a mercury lamp, or an electric arc while confining it in a UV transparent vessel (e.g. quartz). It is detectable in ice water after burning a hydrogen gas stream aimed towards it and is also detectable on floating ice. Rapidly cooling humid air blown through an approximately 2,000 °C spark gap results in detectable amounts. [30]

    A commercially viable process to produce hydrogen peroxide directly from the environment has been of interest for many years. Efficient direct synthesis is difficult to achieve, as the reaction of hydrogen with oxygen thermodynamically favours production of water. Systems for direct synthesis have been developed, most of which employ finely dispersed metal catalysts similar to those used for hydrogenation of organic substrates. [31] [32] One economic obstacle has been that direct processes give a dilute solution uneconomic for transportation. None of these has yet reached a point where it can be used for industrial-scale synthesis.


    Hydrogen peroxide is most commonly available as a solution in water. For consumers, it is usually available from pharmacies at 3 and 6 wt% concentrations. The concentrations are sometimes described in terms of the volume of oxygen gas generated; one milliliter of a 20-volume solution generates twenty milliliters of oxygen gas when completely decomposed. For laboratory use, 30 wt% solutions are most common. Commercial grades from 70% to 98% are also available, but due to the potential of solutions of more than 68% hydrogen peroxide to be converted entirely to steam and oxygen (with the temperature of the steam increasing as the concentration increases above 68%) these grades are potentially far more hazardous and require special care in dedicated storage areas. Buyers must typically allow inspection by commercial manufacturers.

    In 1994, world production of H2O2 was around 1.9 million tonnes and grew to 2.2 million in 2006, [33] most of which was at a concentration of 70% or less. In that year, bulk 30% H2O2 sold for around 0.54 USD/kg, equivalent to US$1.50/kg (US$0.68/lb) on a "100% basis"[ clarification needed ]. [28]

    Natural occurrence

    Hydrogen peroxide occurs in surface water, in groundwater, and in the atmosphere. It forms upon illumination or natural catalytic action by substances contained in water. Sea water contains 0.5 to 14 μg/L of hydrogen peroxide, and freshwater contains 1 to 30 μg/L. [21] Concentrations in air are about 0.4 to 4 μg/m3, varying over several orders of magnitude depending in conditions such as season, altitude, daylight and water vapor content. In rural nighttime air it is less than 0.014 μg/m3, and in moderate photochemical smog it is 14 to 42 μg/m3. [34]



    Hydrogen peroxide decomposes to form water and oxygen with a ΔHo of –2884.5  kJ/kg [35] and a ΔS of 70.5 J/(mol·K):

    The rate of decomposition increases with rise in temperature, concentration, and pH (H2O2 being unstable under alkaline conditions), with cool, dilute, and acidic solutions showing the best stability. Decomposition is catalysed by various redox-active ions or compounds, including most transition metals and their compounds (e.g. manganese dioxide (MnO2), silver, and platinum). [36] Certain metal ions, such as Fe2+ or Ti 3+, can cause the decomposition to take a different path, with free radicals such as the hydroxyl radical (HO) and hydroperoxyl (HOO) being formed. Non-metallic catalysts include potassium iodide (KI), which reacts particularly rapidly and forms the basis of the elephant toothpaste demonstration. Hydrogen peroxide can also be decomposed biologically by the enzyme catalase. The decomposition of hydrogen peroxide liberates oxygen and heat; this can be dangerous, as spilling high-concentration hydrogen peroxide on a flammable substance can cause an immediate fire.

    Redox reactions

    The redox properties of hydrogen peroxide depend on pH as acidic conditions exacerbate the power of oxidizing agents and basic conditions exacerbate the power of reducing agents. As hydrogen peroxide exhibits ambivalent redox properties, being simultaneously an oxidizer or a reductant, its redox behavior immediately depends on pH.

    In acidic solutions, H2O2 is a powerful oxidizer, stronger than chlorine, chlorine dioxide, and potassium permanganate. When used for cleaning laboratory glassware, a solution of hydrogen peroxide and sulfuric acid is referred to as Piranha solution.

    H2O2 is a source of hydroxyl radicals (OH), which are highly reactive.


    F2 HF 3.0
    O3 O2 2.1
    H2O2 H2O 1.8
    KMnO4 MnO2 1.7
    ClO2 HClO 1.5
    Cl2 Cl 1.4

    In acidic solutions, Fe2+ is oxidized to Fe3+ (hydrogen peroxide acting as an oxidizing agent):

    and sulfite (SO2−3) is oxidized to sulfate (SO2−4). However, potassium permanganate is reduced to Mn2+ by acidic H2O2.


    Under alkaline conditions, however, some of these reactions reverse; for example, Mn2+ is oxidized to Mn4+ (as MnO2).

    In basic solutions, hydrogen peroxide is a strong reductant and can reduce a variety of inorganic ions. When H2O2 acts as a reducing agent, oxygen gas is also produced. For example, hydrogen peroxide will reduce sodium hypochlorite and potassium permanganate, which is a convenient method for preparing oxygen in the laboratory:

    Organic reactions

    Hydrogen peroxide is frequently used as an oxidizing agent. Illustrative is oxidation of thioethers to sulfoxides: [38] [39]

    Alkaline hydrogen peroxide is used for epoxidation of electron-deficient alkenes such as acrylic acid derivatives, [40] and for the oxidation of alkylboranes to alcohols, the second step of hydroboration-oxidation. It is also the principal reagent in the Dakin oxidation process.

    Precursor to other peroxide compounds

    Hydrogen peroxide is a weak acid, forming hydroperoxide or peroxide salts with many metals.

    It also converts metal oxides into the corresponding peroxides. For example, upon treatment with hydrogen peroxide, chromic acid (CrO3 and H2SO4) forms a blue peroxide CrO(O2)2.

    This kind of reaction is used industrially to produce peroxoanions. For example, reaction with borax leads to sodium perborate, a bleach used in laundry detergents:

    H2O2 converts carboxylic acids (RCO2H) into peroxy acids (RC(O)O2H), which are themselves used as oxidizing agents. Hydrogen peroxide reacts with acetone to form acetone peroxide and with ozone to form trioxidane. Hydrogen peroxide forms stable adducts with urea (Hydrogen peroxide - urea), sodium carbonate (sodium percarbonate) and other compounds. [41] An acid-base adduct with triphenylphosphine oxide is a useful "carrier" for H2O2 in some reactions.

    Hydrogen peroxide is both an oxidizing agent and reducing agent. The oxidation of hydrogen peroxide by sodium hypochlorite yields singlet oxygen. The net reaction of a ferric ion with hydrogen peroxide is a ferrous ion and oxygen. This proceeds via single electron oxidation and hydroxyl radicals. This is used in some organic chemistry oxidations, e.g. in the Fenton's reagent. Only catalytic quantities of iron ion is needed since peroxide also oxidizes ferrous to ferric ion. The net reaction of hydrogen peroxide and permanganate or manganese dioxide is manganous ion; however, until the peroxide is spent some manganese ions are reoxidized to make the reaction catalytic. This forms the basis for common monopropellant rockets.

    Biological function

    Ascaridole Ascaridol.svg

    Hydrogen peroxide is formed in humans and other animals as a short-lived product in biochemical processes and is toxic to cells. The toxicity is due to oxidation of proteins, membrane lipids and DNA by the peroxide ions. [42] The class of biological enzymes called superoxide dismutase (SOD) is developed in nearly all living cells as an important antioxidant agent. They promote the disproportionation of superoxide into oxygen and hydrogen peroxide, which is then rapidly decomposed by the enzyme catalase to oxygen and water. [43]

    Peroxisomes are organelles found in virtually all eukaryotic cells. [44] They are involved in the catabolism of very long chain fatty acids, branched chain fatty acids, D-amino acids, polyamines, and biosynthesis of plasmalogens, ether phospholipids critical for the normal function of mammalian brains and lungs. [45] Upon oxidation, they produce hydrogen peroxide in the following process catalyzed by flavin adenine dinucleotide (FAD): [46]

    Catalase, another peroxisomal enzyme, uses this H2O2 to oxidize other substrates, including phenols, formic acid, formaldehyde, and alcohol, by means of a peroxidation reaction:

    thus eliminating the poisonous hydrogen peroxide in the process.

    This reaction is important in liver and kidney cells, where the peroxisomes neutralize various toxic substances that enter the blood. Some of the ethanol humans drink is oxidized to acetaldehyde in this way. [47] In addition, when excess H2O2 accumulates in the cell, catalase converts it to H2O through this reaction:

    Another origin of hydrogen peroxide is the degradation of adenosine monophosphate which yields hypoxanthine. Hypoxanthine is then oxidatively catabolized first to xanthine and then to uric acid, and the reaction is catalyzed by the enzyme xanthine oxidase: [48]

    H2O, O2
    Biochem reaction arrow forward YYNN horiz med.svg
    Degradation of hypoxanthine through xanthine to uric acid to form hydrogen peroxide.
    Australian bombardier beetle Pheropsophus verticalis 01 Pengo.jpg
    Australian bombardier beetle

    The degradation of guanosine monophosphate yields xanthine as an intermediate product which is then converted in the same way to uric acid with the formation of hydrogen peroxide. [48]

    Eggs of sea urchin, shortly after fertilization by a sperm, produce hydrogen peroxide. It is then quickly dissociated to HO• radicals. The radicals serve as initiator of radical polymerization, which surrounds the eggs with a protective layer of polymer. [49]

    The bombardier beetle has a device which allows it to shoot corrosive and foul-smelling bubbles at its enemies. The beetle produces and stores hydroquinone and hydrogen peroxide, in two separate reservoirs in the rear tip of its abdomen. When threatened, the beetle contracts muscles that force the two reactants through valved tubes into a mixing chamber containing water and a mixture of catalytic enzymes. When combined, the reactants undergo a violent exothermic chemical reaction, raising the temperature to near the boiling point of water. The boiling, foul-smelling liquid partially becomes a gas (flash evaporation) and is expelled through an outlet valve with a loud popping sound. [50] [51] [52]

    Hydrogen peroxide is a signaling molecule of plant defense against pathogens. [53]

    Hydrogen peroxide has roles as a signalling molecule in the regulation of a wide variety of biological processes. [54] The compound is a major factor implicated in the free-radical theory of aging, based on how readily hydrogen peroxide can decompose into a hydroxyl radical and how superoxide radical byproducts of cellular metabolism can react with ambient water to form hydrogen peroxide. [55] These hydroxyl radicals in turn readily react with and damage vital cellular components, especially those of the mitochondria. [56] [57] [58] At least one study has also tried to link hydrogen peroxide production to cancer. [59] These studies have frequently been quoted in fraudulent treatment claims.[ citation needed ]

    The amount of hydrogen peroxide in biological systems can be assayed using a fluorometric assay. [60]



    About 60% of the world's production of hydrogen peroxide is used for pulp- and paper-bleaching. [33] The second major industrial application is the manufacture of sodium percarbonate and sodium perborate, which are used as mild bleaches in laundry detergents. Sodium percarbonate, which is an adduct of sodium carbonate and hydrogen peroxide, is the active ingredient in such laundry products as OxiClean and Tide laundry detergent. When dissolved in water, it releases hydrogen peroxide and sodium carbonate, [20] By themselves these bleaching agents are only effective at wash temperatures of 60 °C (140 °F) or above and so, often are used in conjunction with bleach activators, which facilitate cleaning at lower temperatures. It has also been used as a flour bleaching agent and a tooth whitening agent.

    Production of organic compounds

    It is used in the production of various organic peroxides with dibenzoyl peroxide being a high volume example. Peroxy acids, such as peracetic acid and meta-chloroperoxybenzoic acid also are produced using hydrogen peroxide. Hydrogen peroxide has been used for creating organic peroxide-based explosives, such as acetone peroxide. It is used as an initiator in polymerizations.

    Sewage treatment

    Hydrogen peroxide is used in certain waste-water treatment processes to remove organic impurities. In advanced oxidation processing, the Fenton reaction [61] [62] gives the highly reactive hydroxyl radical (•OH). This degrades organic compounds, including those that are ordinarily robust, such as aromatic or halogenated compounds. [63] It can also oxidize sulfur-based compounds present in the waste; which is beneficial as it generally reduces their odour. [64]


    Hydrogen peroxide may be used for the sterilization of various surfaces, [65] including surgical tools, [66] and may be deployed as a vapour (VHP) for room sterilization. [67] H2O2 demonstrates broad-spectrum efficacy against viruses, bacteria, yeasts, and bacterial spores. [68] [69] In general, greater activity is seen against Gram-positive than Gram-negative bacteria; however, the presence of catalase or other peroxidases in these organisms may increase tolerance in the presence of lower concentrations. [70] Lower levels of concentration (3%) will work against most spores; higher concentrations (7 to 30%) and longer contact times will improve sporicidal activity. [69] [71]

    Hydrogen peroxide is seen as an environmentally safe alternative to chlorine-based bleaches, as it degrades to form oxygen and water and it is generally recognized as safe as an antimicrobial agent by the U.S. Food and Drug Administration (FDA). [72]


    Rocket-belt hydrogen-peroxide propulsion system used in a jet pack Rocket Belt Propulsion.svg
    Rocket-belt hydrogen-peroxide propulsion system used in a jet pack

    High-concentration H2O2 is referred to as "high-test peroxide" (HTP). It can be used either as a monopropellant (not mixed with fuel) or as the oxidizer component of a bipropellant rocket. Use as a monopropellant takes advantage of the decomposition of 70–98% concentration hydrogen peroxide into steam and oxygen. The propellant is pumped into a reaction chamber, where a catalyst, usually a silver or platinum screen, triggers decomposition, producing steam at over 600 °C (1,100 °F), which is expelled through a nozzle, generating thrust. H2O2 monopropellant produces a maximal specific impulse (Isp) of 161 s (1.6 kN·s/kg). Peroxide was the first major monopropellant adopted for use in rocket applications. Hydrazine eventually replaced hydrogen-peroxide monopropellant thruster applications primarily because of a 25% increase in the vacuum specific impulse. [73] Hydrazine (toxic) and hydrogen peroxide (less-toxic [ACGIH TLV 0.01 and 1 ppm respectively]) are the only two monopropellants (other than cold gases) to have been widely adopted and utilized for propulsion and power applications.[ citation needed ] The Bell Rocket Belt, reaction control systems for X-1, X-15, Centaur, Mercury, Little Joe, as well as the turbo-pump gas generators for X-1, X-15, Jupiter, Redstone and Viking used hydrogen peroxide as a monopropellant. [74]

    As a bipropellant, H2O2 is decomposed to burn a fuel as an oxidizer. Specific impulses as high as 350 s (3.5 kN·s/kg) can be achieved, depending on the fuel. Peroxide used as an oxidizer gives a somewhat lower Isp than liquid oxygen, but is dense, storable, non-cryogenic and can be more easily used to drive gas turbines to give high pressures using an efficient closed cycle. It may also be used for regenerative cooling of rocket engines. Peroxide was used very successfully as an oxidizer in World War II German rocket motors (e.g. T-Stoff, containing oxyquinoline stabilizer, for both the Walter HWK 109-500 Starthilfe RATO externally podded monopropellant booster system, and for the Walter HWK 109-509 rocket motor series used for the Me 163B), most often used with C-Stoff in a self-igniting hypergolic combination, and for the low-cost British Black Knight and Black Arrow launchers. Presently, HTP is used on ILR-33 AMBER [75] and Nucleus [76] suborbital rockets.

    In the 1940s and 1950s, the Hellmuth Walter KG–conceived turbine used hydrogen peroxide for use in submarines while submerged; it was found to be too noisy and require too much maintenance compared to diesel-electric power systems. Some torpedoes used hydrogen peroxide as oxidizer or propellant. Operator error in the use of hydrogen-peroxide torpedoes was named as possible causes for the sinking of HMS Sidon and the Russian submarine Kursk. [77] SAAB Underwater Systems is manufacturing the Torpedo 2000. This torpedo, used by the Swedish Navy, is powered by a piston engine propelled by HTP as an oxidizer and kerosene as a fuel in a bipropellant system. [78] [79]

    Household use

    Contact lenses soaking in a 3% hydrogen peroxide-based solution. The case includes a catalytic disc which neutralises the hydrogen peroxide over time. Contact lens case for Hydrogen Peroxide solution showing bubbles.jpg
    Contact lenses soaking in a 3% hydrogen peroxide-based solution. The case includes a catalytic disc which neutralises the hydrogen peroxide over time.

    Hydrogen peroxide has various domestic uses, primarily as a cleaning and disinfecting agent.

    Hair bleaching

    Diluted H2O2 (between 1.9% and 12%) mixed with aqueous ammonia has been used to bleach human hair. The chemical's bleaching property lends its name to the phrase "peroxide blonde". [80] Hydrogen peroxide is also used for tooth whitening. It may be found in most whitening toothpastes. Hydrogen peroxide has shown positive results involving teeth lightness and chroma shade parameters. [81] It works by oxidizing colored pigments onto the enamel where the shade of the tooth may become lighter.[ further explanation needed ] Hydrogen peroxide may be mixed with baking soda and salt to make a homemade toothpaste. [82]

    Removal of blood stains

    Hydrogen peroxide reacts with blood as a bleaching agent, and so if a blood stain is fresh, or not too old, liberal application of hydrogen peroxide, if necessary in more than single application, will bleach the stain fully out. After about two minutes of the application, the blood should be firmly blotted out. [83] [84]

    Acne treatment

    Hydrogen peroxide may be used to treat acne, [85] although benzoyl peroxide is a more common treatment.

    Niche uses

    Chemiluminescence of cyalume, as found in a glow stick Chemiluminescance.JPG
    Chemiluminescence of cyalume, as found in a glow stick
    Glow sticks

    Hydrogen peroxide reacts with certain di-esters, such as phenyl oxalate ester (cyalume), to produce chemiluminescence; this application is most commonly encountered in the form of glow sticks.


    Some horticulturalists and users of hydroponics advocate the use of weak hydrogen peroxide solution in watering solutions. Its spontaneous decomposition releases oxygen that enhances a plant's root development and helps to treat root rot (cellular root death due to lack of oxygen) and a variety of other pests. [86] [87]

    For general watering concentrations around 0.1% is in use and this can be increased up to one percent for anti-fungal actions. [88] Tests show that plant foliage can safely tolerate concentrations up to 3%. [89]


    Hydrogen peroxide is used in aquaculture for controlling mortality caused by various microbes. In 2019, the U.S. FDA approved it for control of Saprolegniasis in all coldwater finfish and all fingerling and adult coolwater and warmwater finfish, for control of external columnaris disease in warm-water finfish, and for control of Gyrodactylus spp. in freshwater-reared salmonids. [90] Laboratory tests conducted by fish culturists have demonstrated that common household hydrogen peroxide may be used safely to provide oxygen for small fish. The hydrogen peroxide releases oxygen by decomposition when it is exposed to catalysts such as manganese dioxide.

    Removing yellowing from aged plastics

    Hydrogen peroxide may be used in combination with a UV-light source to remove yellowing from white or light grey acrylonitrile butadiene styrene (ABS) plastics to partially or fully restore the original color. In the retrocomputing scene, this process is commonly referred to as retr0bright.


    Skin shortly after exposure to 35%
H2O2 Hydrogen peroxide 35 percent on skin.jpg
    Skin shortly after exposure to 35% H2O2

    Regulations vary, but low concentrations, such as 5%, are widely available and legal to buy for medical use. Most over-the-counter peroxide solutions are not suitable for ingestion. Higher concentrations may be considered hazardous and typically are accompanied by a safety data sheet (SDS). In high concentrations, hydrogen peroxide is an aggressive oxidizer and will corrode many materials, including human skin. In the presence of a reducing agent, high concentrations of H2O2 will react violently. [91] While concentrations up to 35% produce only "white" oxygen bubbles in the skin (and some biting pain) that disappear with the blood within 30-45 minutes concentrations of 98% dissolve paper. However concentrations as low as 3% can be dangerous for the eye because of oxygen evolution within the eye. [92]

    High-concentration hydrogen peroxide streams, typically above 40%, should be considered hazardous due to concentrated hydrogen peroxide's meeting the definition of a DOT oxidizer according to U.S. regulations, if released into the environment. The EPA Reportable Quantity (RQ) for D001 hazardous wastes is 100 pounds (45 kg), or approximately 10 US gallons (38 L), of concentrated hydrogen peroxide.

    Hydrogen peroxide should be stored in a cool, dry, well-ventilated area and away from any flammable or combustible substances. It should be stored in a container composed of non-reactive materials such as stainless steel or glass (other materials including some plastics and aluminium alloys may also be suitable). [93] Because it breaks down quickly when exposed to light, it should be stored in an opaque container, and pharmaceutical formulations typically come in brown bottles that block light. [94]

    Hydrogen peroxide, either in pure or diluted form, may pose several risks, the main one being that it forms explosive mixtures upon contact with organic compounds. [95] Distillation of hydrogen peroxide at normal pressures is highly dangerous. It is also corrosive, especially when concentrated, but even domestic-strength solutions may cause irritation to the eyes, mucous membranes, and skin. [96] Swallowing hydrogen peroxide solutions is particularly dangerous, as decomposition in the stomach releases large quantities of gas (ten times the volume of a 3% solution), leading to internal bloating. Inhaling over 10% can cause severe pulmonary irritation. [97]

    With a significant vapour pressure (1.2 kPa at 50 °C), [98] hydrogen-peroxide vapour is potentially hazardous. According to U.S. NIOSH, the immediately dangerous to life and health (IDLH) limit is only 75 ppm. [99] The U.S. Occupational Safety and Health Administration (OSHA) has established a permissible exposure limit of 1.0 ppm calculated as an 8-hour time-weighted average (29 CFR 1910.1000, Table Z-1). [95] Hydrogen peroxide also has been classified by the American Conference of Governmental Industrial Hygienists (ACGIH) as a "known animal carcinogen, with unknown relevance on humans". [100] For workplaces where there is a risk of exposure to the hazardous concentrations of the vapours, continuous monitors for hydrogen peroxide should be used. Information on the hazards of hydrogen peroxide is available from OSHA [95] and from the ATSDR. [101]

    Wound healing

    Historically, hydrogen peroxide was used for disinfecting wounds, partly because of its low cost and prompt availability compared to other antiseptics. [102]

    There is conflicting evidence on hydrogen peroxide's effect on wound healing. Some research finds benefit, while other research find delays and healing inhibition. [103] Its use for home treatment of wounds is generally contraindicated. [104] 1.5–3% Hydrogen peroxide is used as a desinfectant in dentistry, especially in endodotic treatments together with hypochlorite and chlorhexidin and 1–1.5% is also useful for treatment of inflammation of third molars (wisdom teeth). [105]

    Use in alternative medicine

    Practitioners of alternative medicine have advocated the use of hydrogen peroxide for various conditions, including emphysema, influenza, AIDS, and in particular cancer. [106] There is no evidence of effectiveness and in some cases it has proved fatal. [107] [108] [109] [110] [111]

    Both the effectiveness and safety of hydrogen peroxide therapy is scientifically questionable. Hydrogen peroxide is produced by the immune system, but in a carefully controlled manner. Cells called phagocytes engulf pathogens and then use hydrogen peroxide to destroy them. The peroxide is toxic to both the cell and the pathogen and so is kept within a special compartment, called a phagosome. Free hydrogen peroxide will damage any tissue it encounters via oxidative stress, a process that also has been proposed as a cause of cancer. [112] Claims that hydrogen peroxide therapy increases cellular levels of oxygen have not been supported. The quantities administered would be expected to provide very little additional oxygen compared to that available from normal respiration. It is also difficult to raise the level of oxygen around cancer cells within a tumour, as the blood supply tends to be poor, a situation known as tumor hypoxia.

    Large oral doses of hydrogen peroxide at a 3% concentration may cause irritation and blistering to the mouth, throat, and abdomen as well as abdominal pain, vomiting, and diarrhea. [107] Ingestion of hydrogen peroxide at concentrations of 35% or higher has been implicated as the cause of numerous gas embolism events resulting in hospitalisation. In these cases, hyperbaric oxygen therapy was used to treat the embolisms. [113]

    Intravenous injection of hydrogen peroxide has been linked to several deaths. [109] [110] [111] The American Cancer Society states that "there is no scientific evidence that hydrogen peroxide is a safe, effective, or useful cancer treatment." [108] Furthermore, the therapy is not approved by the U.S. FDA.

    Historical incidents

    See also

    Related Research Articles

    <span class="mw-page-title-main">Sulfuric acid</span> Chemical compound (H₂SO₄)

    Sulfuric acid or sulphuric acid, known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formula H2SO4. It is a colorless, odorless and viscous liquid that is miscible with water.

    <span class="mw-page-title-main">Catalase</span> Biocatalyst decomposing hydrogen peroxide

    Catalase is a common enzyme found in nearly all living organisms exposed to oxygen which catalyzes the decomposition of hydrogen peroxide to water and oxygen. It is a very important enzyme in protecting the cell from oxidative damage by reactive oxygen species (ROS). Catalase has one of the highest turnover numbers of all enzymes; one catalase molecule can convert millions of hydrogen peroxide molecules to water and oxygen each second.

    Monopropellants are propellants consisting of chemicals that release energy through exothermic chemical decomposition. The molecular bond energy of the monopropellant is released usually through use of a catalyst. This can be contrasted with bipropellants that release energy through the chemical reaction between an oxidizer and a fuel. While stable under defined storage conditions, monopropellants decompose very rapidly under certain other conditions to produce a large volume of its own energetic (hot) gases for the performance of mechanical work. Although solid deflagrants such as nitrocellulose, the most commonly used propellant in firearms, could be thought of as monopropellants, the term is usually reserved for liquids in engineering literature.

    <span class="mw-page-title-main">Oxidizing agent</span> Chemical compound used to oxidize another substance in a chemical reaction

    An oxidizing agent is a substance in a redox chemical reaction that gains or "accepts"/"receives" an electron from a reducing agent. In other words, an oxidizer is any substance that oxidizes another substance. The oxidation state, which describes the degree of loss of electrons, of the oxidizer decreases while that of the reductant increases; this is expressed by saying that oxidizers "undergo reduction" and "are reduced" while reducers "undergo oxidation" and "are oxidized". Common oxidizing agents are oxygen, hydrogen peroxide and the halogens.

    <span class="mw-page-title-main">Sodium hypochlorite</span> Chemical compound (known in solution as bleach)

    Sodium hypochlorite, commonly known in a dilute solution as (chlorine) bleach, is an inorganic chemical compound with the formula NaOCl, comprising a sodium cation and a hypochlorite anion. It may also be viewed as the sodium salt of hypochlorous acid. The anhydrous compound is unstable and may decompose explosively. It can be crystallized as a pentahydrate NaOCl·5H
    , a pale greenish-yellow solid which is not explosive and is stable if kept refrigerated.

    <span class="mw-page-title-main">Sodium percarbonate</span> Chemical compound

    Sodium percarbonate is a chemical substance with formula Na
    . It is an adduct of sodium carbonate and hydrogen peroxide whose formula is more properly written as 2 Na
     · 3 H
    . It is a colorless, crystalline, hygroscopic and water-soluble solid. It is sometimes abbreviated as SPC. It contains 32.5% by weight of hydrogen peroxide.

    <span class="mw-page-title-main">Chlorine dioxide</span> Chemical compound

    Chlorine dioxide is a chemical compound with the formula ClO2 that exists as yellowish-green gas above 11 °C, a reddish-brown liquid between 11 °C and −59 °C, and as bright orange crystals below −59 °C. It is usually handled as an aqueous solution. It is also commonly used as a bleach. More recent developments have extended its applications in food processing and as a disinfectant.

    <span class="mw-page-title-main">Disinfectant</span> Antimicrobial agent that inactivates or destroys microbes

    A disinfectant is a chemical substance or compound used to inactivate or destroy microorganisms on inert surfaces. Disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores; it is less effective than sterilization, which is an extreme physical or chemical process that kills all types of life. Disinfectants are generally distinguished from other antimicrobial agents such as antibiotics, which destroy microorganisms within the body, and antiseptics, which destroy microorganisms on living tissue. Disinfectants are also different from biocides—the latter are intended to destroy all forms of life, not just microorganisms. Disinfectants work by destroying the cell wall of microbes or interfering with their metabolism. It is also a form of decontamination, and can be defined as the process whereby physical or chemical methods are used to reduce the amount of pathogenic microorganisms on a surface.

    <span class="mw-page-title-main">Hydrogen peroxide - urea</span> Chemical compound

    Hydrogen peroxide - urea is a solid composed of equal amounts of hydrogen peroxide and urea. This compound is a white crystalline solid which dissolves in water to give free hydrogen peroxide. Hydrogen peroxide - urea contains solid and water-free hydrogen peroxide, which offers a higher stability and better controllability than liquid hydrogen peroxide when used as an oxidizing agent. Often called carbamide peroxide in the dental office, it is used as a source of hydrogen peroxide for bleaching, disinfection, and oxidation.

    <span class="mw-page-title-main">Hypochlorite</span> Ion

    In chemistry, hypochlorite is an anion with the chemical formula ClO. It combines with a number of cations to form hypochlorite salts. Common examples include sodium hypochlorite and calcium hypochlorite. The Cl-O distance in ClO is 1.69 Å.

    <span class="mw-page-title-main">Sodium chlorate</span> Chemical compound

    Sodium chlorate is an inorganic compound with the chemical formula NaClO3. It is a white crystalline powder that is readily soluble in water. It is hygroscopic. It decomposes above 300 °C to release oxygen and leaves sodium chloride. Several hundred million tons are produced annually, mainly for applications in bleaching pulp to produce high brightness paper.

    Fenton's reagent is a solution of hydrogen peroxide (H2O2) with ferrous iron (typically iron(II) sulfate, FeSO4) as a catalyst that is used to oxidize contaminants or waste waters as part of an advanced oxidation process. Fenton's reagent can be used to destroy organic compounds such as trichloroethylene (TCE) and tetrachloroethylene (perchloroethylene, PCE). It was developed in the 1890s by Henry John Horstman Fenton as an analytical reagent.

    <span class="mw-page-title-main">Iodic acid</span> Chemical compound (HIO3)

    Iodic acid is a white water-soluble solid with the chemical formula HIO3. Its robustness contrasts with the instability of chloric acid and bromic acid. Iodic acid features iodine in the oxidation state +5 and is one of the most stable oxo-acids of the halogens. When heated, samples dehydrate to give iodine pentoxide. On further heating, the iodine pentoxide further decomposes, giving a mix of iodine, oxygen and lower oxides of iodine.

    <span class="mw-page-title-main">Organic peroxides</span> Organic compounds of the form R–O–O–R’

    In organic chemistry, organic peroxides are organic compounds containing the peroxide functional group. If the R′ is hydrogen, the compounds are called hydroperoxides, which are discussed in that article. The O−O bond of peroxides easily breaks, producing free radicals of the form RO. Thus, organic peroxides are useful as initiators for some types of polymerization, such as the acrylic, unsaturated polyester, and vinyl ester resins used in glass-reinforced plastics. MEKP and benzoyl peroxide are commonly used for this purpose. However, the same property also means that organic peroxides can explosively combust. Organic peroxides, like their inorganic counterparts, are often powerful bleaching agents.

    <span class="mw-page-title-main">Piranha solution</span> [Per-hexa-sulfuric acid] is an oxidizing acid mixture containing sulfuric acid and hydrogen peroxide

    Piranha solution, also known as piranha etch, is a mixture of sulfuric acid (H2SO4) and hydrogen peroxide (H2O2). The result of the mixture gives rise to a strong union of two acids called per-hexa-sulfuric acid (H4SO6) that is used to clean organic residues off substrates. Because the mixture is a strong oxidizing agent, it will decompose most organic matter, and it will also hydroxylate most surfaces (by adding –OH groups), making them highly hydrophilic (water-compatible). This means the solution can also easily dissolve fabric and skin, potentially causing severe damage and chemical burns in case of inadvertent contact.

    <span class="mw-page-title-main">Dakin oxidation</span>

    The Dakin oxidation is an organic redox reaction in which an ortho- or para-hydroxylated phenyl aldehyde or ketone reacts with hydrogen peroxide in base to form a benzenediol and a carboxylate. Overall, the carbonyl group is oxidised, whereas the H2O2 is reduced.

    <span class="mw-page-title-main">Bleach</span> Chemical used to remove stains, whiten, or disinfect, often via oxidation

    Bleach is the generic name for any chemical product that is used industrially or domestically to remove color (whitening) from a fabric or fiber or to clean or to remove stains in a process called bleaching. It often refers specifically to a dilute solution of sodium hypochlorite, also called "liquid bleach".

    Bleaching of wood pulp is the chemical processing of wood pulp to lighten its color and whiten the pulp. The primary product of wood pulp is paper, for which whiteness is an important characteristic. These processes and chemistry are also applicable to the bleaching of non-wood pulps, such as those made from bamboo or kenaf.

    <span class="mw-page-title-main">Oxygen compounds</span>

    The oxidation state of oxygen is −2 in almost all known compounds of oxygen. The oxidation state −1 is found in a few compounds such as peroxides. Compounds containing oxygen in other oxidation states are very uncommon: −12 (superoxides), −13 (ozonides), 0, +12 (dioxygenyl), +1, and +2.

    <span class="mw-page-title-main">Metal peroxide</span>

    Metal peroxides are metal-containing compounds with ionically- or covalently-bonded peroxide (O2−
    ) groups. This large family of compounds can be divided into ionic and covalent peroxide. The first class mostly contains the peroxides of the alkali and alkaline earth metals whereas the covalent peroxides are represented by such compounds as hydrogen peroxide and peroxymonosulfuric acid (H2SO5). In contrast to the purely ionic character of alkali metal peroxides, peroxides of transition metals have a more covalent character.



    1. Easton MF, Mitchell AG, Wynne-Jones WF (1952). "The behaviour of mixtures of hydrogen peroxide and water. Part 1.—Determination of the densities of mixtures of hydrogen peroxide and water". Transactions of the Faraday Society. 48: 796–801. doi:10.1039/TF9524800796. S2CID   96669623. Archived from the original on 15 February 2022. Retrieved 30 November 2019.
    2. "Hydrogen peroxide". www.chemsrc.com. Archived from the original on 8 August 2017. Retrieved 3 May 2018.
    3. 1 2 3 4 NIOSH Pocket Guide to Chemical Hazards. "#0335". National Institute for Occupational Safety and Health (NIOSH).
    4. 1 2 3 "Hydrogen peroxide". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
    5. Housecroft CE, Sharpe AG (2005). Inorganic Chemistry (2nd ed.). Pearson Prentice-Hall. p. 443. ISBN   0130-39913-2.
    6. Hill CN (2001). A Vertical Empire: The History of the UK Rocket launch and Space Programme, 1950–1971. Imperial College Press. ISBN   978-1-86094-268-6. Archived from the original on 13 April 2021. Retrieved 24 August 2020.
    7. Brauer G, ed. (1963). Handbook of preparative inorganic chemistry. Vol. 1. Translation editing by Reed F. (2nd ed.). New York: Academic Press. p. 140. ISBN   978-0-12-126601-1.
    8. Giguère PA (1950). "The Infra‐Red Spectrum of Hydrogen Peroxide" (PDF). Journal of Chemical Physics. 18 (1): 88. Bibcode:1950JChPh..18...88G. doi:10.1063/1.1747464. Archived (PDF) from the original on 2 December 2017. Retrieved 31 December 2018.
    9. Giguère PA (1983). "Molecular association and structure of hydrogen peroxide". Journal of Chemical Education . 60 (5): 399–401. Bibcode:1983JChEd..60..399G. doi:10.1021/ed060p399.
    10. Hunt RH, Leacock RA, Peters CW, Hecht KT (1965). "Internal-Rotation in Hydrogen Peroxide: The Far-Infrared Spectrum and the Determination of the Hindering Potential" (PDF). The Journal of Chemical Physics. 42 (6): 1931. Bibcode:1965JChPh..42.1931H. doi:10.1063/1.1696228. hdl: 2027.42/71115 . Archived (PDF) from the original on 9 April 2014. Retrieved 9 April 2014.
    11. Ball R, Brindley J (March 2016). "The Life Story of Hydrogen Peroxide III: Chirality and Physical Effects at the Dawn of Life". Origins of Life and Evolution of the Biosphere. 46 (1): 81–93. Bibcode:2016OLEB...46...81B. doi:10.1007/s11084-015-9465-y. PMID   26399407. S2CID   9564774.
    12. Dougherty DA, Anslyn EV (2005). Modern Physical Organic Chemistry. University Science. p. 122. ISBN   978-1-891389-31-3.
    13. Abrahams SC, Collin RL, Lipscomb WN (1 January 1951). "The crystal structure of hydrogen peroxide". Acta Crystallographica. 4 (1): 15–20. doi: 10.1107/S0365110X51000039 .
    14. "Hydrogen Peroxide Technical Library" (PDF). Archived from the original (PDF) on 29 December 2009. Retrieved 3 March 2016.
    15. Flohé L (December 2020). "Looking Back at the Early Stages of Redox Biology". Antioxidants. 9 (12): 1254. doi: 10.3390/antiox9121254 . PMC   7763103 . PMID   33317108. I checked Humboldt's pertinent publication carefully, but was unable to find an unambiguous proof of this assumption; the description of the starting materials ("Alaun-Erden" or "schwere Erden") were just too unprecise to understand what kind of chemical experiments he performed.
    16. Gilbert LW (1820). "Der tropfbar flüssige Sauerstoff, oder das oxygenierte Wasser". Annals of Physics (in German). 65–66 (1): 3. Bibcode:1820AnP....64....1T. doi:10.1002/andp.18200640102.
    17. Thénard LJ (1818). "Observations sur des nouvelles combinaisons entre l'oxigène et divers acides". Annales de chimie et de physique . 2nd series. 8: 306–312. Archived from the original on 3 September 2016. Retrieved 9 February 2016.
    18. Giguère PA. "Hydrogen peroxide". Access Science. McGraw-Hill Education. doi:10.1036/1097-8542.329200. Archived from the original on 30 November 2018. Retrieved 28 November 2018. Hydrogen peroxide was discovered in 1818 by the French chemist Louis-Jacques Thenard, who named it eau oxygénée (oxygenated water).
    19. Preiato D (5 March 2020). "What is oxygenated water?". Healthline. Healthline Media. Archived from the original on 31 October 2020. Retrieved 23 September 2020.
    20. 1 2 Jones CW, Clark JH (1999). Applications of Hydrogen Peroxide and Derivatives. Royal Society of Chemistry. ISBN   978-0-85404-536-5.
    21. 1 2 Offermanns H, Dittrich G, Steiner N (2000). "Wasserstoffperoxid in Umweltschutz und Synthese". Chemie in unserer Zeit. 34 (3): 150. doi:10.1002/1521-3781(200006)34:3<150::AID-CIUZ150>3.0.CO;2-A.
    22. Wolffenstein R (October 1894). "Concentration und Destillation von Wasserstoffsuperoxyd". Berichte der Deutschen Chemischen Gesellschaft (in German). 27 (3): 3307–3312. doi:10.1002/cber.189402703127. Archived from the original on 13 February 2016. Retrieved 29 June 2014.
    23. Carrara G (1892). "Sul peso molecolare e sul potere rifrangente dell' acqua ossigenata" [On the molecular weight and on the refracting power of hydrogen peroxide]. Atti della Reale Accademia dei Lincei. 1 (2): 19–24. Archived from the original on 4 September 2016.
      Carrara's findings were confirmed by: W. R. Orndorff and John White (1893) "The molecular weight of hydrogen peroxide and of benzoyl peroxide," Archived 4 September 2016 at the Wayback Machine American Chemical Journal, 15 : 347–356.
    24. See, for example:
      • In 1882, Kingzett proposed as a structure H2O=O. See: Kingzett T (29 September 1882). "On the activity of oxygen and the mode of formation of hydrogen dioxide". The Chemical News. 46 (1192): 141–142. Archived from the original on 3 September 2016. Retrieved 9 February 2016.
      • In his 1922 textbook, Joseph Mellor considered three hypothetical molecular structures for hydrogen peroxide, admitting (p. 952): "... the constitution of this compound has not been yet established by unequivocal experiments". See: Joseph William Mellor, A Comprehensive Treatise on Inorganic and Theoretical Chemistry, vol. 1 (London, England: Longmans, Green and Co., 1922), p. 952–956. Archived 3 September 2016 at the Wayback Machine
      • W. C. Schumb, C. N. Satterfield, and R. L. Wentworth (1 December 1953) "Report no. 43: Hydrogen peroxide, Part two" Archived 26 February 2015 at the Wayback Machine , Office of Naval Research, Contract No. N5ori-07819 On p. 178, the authors present six hypothetical models (including cis-trans isomers) for hydrogen peroxide's molecular structure. On p. 184, the present structure is considered almost certainly correct—although a small doubt remained. (Note: The report by Schumb et al. was reprinted as: W. C. Schumb, C. N. Satterfield, and R. L. Wentworth, Hydrogen Peroxide (New York, New York: Reinhold Publishing Corp. (American Chemical Society Monograph), 1955).)
    25. Penney WG, Sutherland GB (1934). "The theory of the structure of hydrogen peroxide and hydrazine". Journal of Chemical Physics. 2 (8): 492–498. Bibcode:1934JChPh...2..492P. doi:10.1063/1.1749518.
    26. Penney WG, Sutherland GB (1934). "A note on the structure of H2O2 and H4N2 with particular reference to electric moments and free rotation". Transactions of the Faraday Society. 30: 898–902. doi:10.1039/tf934300898b.
    27. "Preparing to manufacture hydrogen peroxide" (PDF). IDC Technologies. Archived (PDF) from the original on 3 August 2021. Retrieved 14 February 2022.
    28. 1 2 3 Campos-Martin JM, Blanco-Brieva G, Fierro JL (October 2006). "Hydrogen peroxide synthesis: an outlook beyond the anthraquinone process". Angewandte Chemie. 45 (42): 6962–6984. doi:10.1002/anie.200503779. PMID   17039551. S2CID   23286196.
    29. H. Riedl and G. Pfleiderer, U.S. Patent 2,158,525 (2 October 1936 in USA, and 10 October 1935 in Germany) to I. G. Farbenindustrie, Germany
    30. Mellor JW (1922). Modern Inorganic Chemistry. Longmans, Green and Co. pp. 192–195.
    31. Noritaka Mizuno Gabriele Centi, Siglinda Perathoner, Salvatore Abate "Direct Synthesis of Hydrogen Peroxide: Recent Advances" in Modern Heterogeneous Oxidation Catalysis: Design, Reactions and Characterization 2009, Wiley-VCH. doi : 10.1002/9783527627547.ch8
    32. Edwards JK, Solsona B, N EN, Carley AF, Herzing AA, Kiely CJ, Hutchings GJ (February 2009). "Switching off hydrogen peroxide hydrogenation in the direct synthesis process". Science. 323 (5917): 1037–1041. Bibcode:2009Sci...323.1037E. doi:10.1126/science.1168980. PMID   19229032. S2CID   1828874. Archived from the original on 15 February 2022. Retrieved 30 November 2019.
    33. 1 2 Hage R, Lienke A (December 2005). "Applications of transition-metal catalysts to textile and wood-pulp bleaching". Angewandte Chemie. 45 (2): 206–222. doi:10.1002/anie.200500525. PMID   16342123. Archived from the original on 25 January 2022. Retrieved 14 February 2022.
    34. Special Report No. 10. Hydrogen Peroxide. OEL Criteria Document. CAS No. 7722-84-1. July 1996.
    35. "Decomposition of Hydrogen Peroxide - Kinetics and Review of Chosen Catalysts" (PDF). Archived (PDF) from the original on 22 December 2018. Retrieved 30 August 2019.
    36. Petrucci RH (2007). General Chemistry: Principles & Modern Applications (9th ed.). Prentice Hall. p.  606. ISBN   978-0-13-149330-8.
    37. Housecroft CE, Sharpe AG (2005). Inorganic Chemistry (2nd ed.). Pearson Prentice-Hall. p. 444. ISBN   0130-39913-2.
    38. Ravikumar KS, Kesavan V, Crousse B, Bonnet-Delpon D, Bégué JP (2003). "Mild and Selective Oxidation of Sulfur Compounds in Trifluoroethanol: Diphenyldisulfide and Methyl phenyl Sulfoxide". Org. Synth. 80: 184. doi:10.15227/orgsyn.080.0184.
    39. Xu WL, Li YZ, Zhang QS, Zhu HS (2004). "A Selective, Convenient, and Efficient Conversion of Sulfides to Sulfoxides". Synthesis (2): 227–232. doi:10.1055/s-2004-44387.
    40. Mayer RJ, Ofial AR (May 2018). "Nucleophilic Reactivities of Bleach Reagents". Organic Letters. 20 (10): 2816–2820. doi:10.1021/acs.orglett.8b00645. PMID   29741385.
    41. Chernyshov IY, Vener MV, Prikhodchenko PV, Medvedev AG, Lev O, Churakov AV (4 January 2017). "Peroxosolvates: Formation Criteria, H2O2 Hydrogen Bonding, and Isomorphism with the Corresponding Hydrates". Crystal Growth & Design. 17 (1): 214–220. doi:10.1021/acs.cgd.6b01449. ISSN   1528-7483.
    42. Löffler G. and Petrides, P. E. Physiologische Chemie. 4 ed., p. 288, Springer, Berlin 1988, ISBN   3-540-18163-6 (in German)
    43. Löffler G. and Petrides, P. E. Physiologische Chemie. 4 ed., pp. 321–322, Springer, Berlin 1988, ISBN   3-540-18163-6 (in German)
    44. Gabaldón T (March 2010). "Peroxisome diversity and evolution". Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 365 (1541): 765–773. doi:10.1098/rstb.2009.0240. PMC   2817229 . PMID   20124343.
    45. Wanders RJ, Waterham HR (2006). "Biochemistry of mammalian peroxisomes revisited". Annual Review of Biochemistry. 75 (1): 295–332. doi:10.1146/annurev.biochem.74.082803.133329. PMID   16756494.
    46. Nelson D, Cox C, Lehninger AL, Cox MM (2001). Lehninger Biochemie (in German). Springer. pp. 663–664. ISBN   3-540-41813-X. Archived from the original on 28 February 2017.
    47. Riley, Edward P. et al. (ed.) Fetal Alcoholspectrum Disorder Fasd: Management and Policy Perspectives Archived 28 February 2017 at the Wayback Machine , Wiley-VCH, 2010, ISBN   3-527-32839-4 p. 112
    48. 1 2 Nelson, David; Cox, Michael; Lehninger, Albert L. and Cox, Michael M. Lehninger Biochemie, p. 932, Springer, 2001, ISBN   3-540-41813-X (in German)
    49. Kröger M (1989). "History". Chemie in unserer Zeit. 23: 34–35. doi:10.1002/ciuz.19890230106.
    50. Schildknecht H, Holoubek K (1961). "The bombardier beetle and its chemical explosion". Angewandte Chemie. 73: 1–7. doi:10.1002/ange.19610730102.
    51. Weber CG (Winter 1981). "The Bombadier Beetle Myth Exploded". Creation/Evolution. 2 (1): 1–5. Archived from the original on 29 September 2017. Retrieved 12 November 2017.
    52. Isaak M (30 May 2003). "Bombardier Beetles and the Argument of Design". TalkOrigins Archive . Archived from the original on 16 November 2017. Retrieved 12 November 2017.
    53. "Wie Pflanzen sich schützen, Helmholtz-Institute of Biochemical Plant Pathology (in German)" (PDF) (in German). Helmholtz-Institute of Biochemical Plant Pathology. Archived from the original (PDF) on 23 July 2011. Retrieved 14 February 2022.
    54. Veal EA, Day AM, Morgan BA (April 2007). "Hydrogen peroxide sensing and signaling". Molecular Cell. 26 (1): 1–14. doi: 10.1016/j.molcel.2007.03.016 . PMID   17434122.
    55. Weindruch R (1 December 2006). "Calorie Restriction and Aging". Scientific American . Archived from the original on 14 February 2022. Retrieved 14 February 2022.
    56. Giorgio M, Trinei M, Migliaccio E, Pelicci PG (September 2007). "Hydrogen peroxide: a metabolic by-product or a common mediator of ageing signals?". Nature Reviews. Molecular Cell Biology. 8 (9): 722–728. doi:10.1038/nrm2240. PMID   17700625. S2CID   6407526. Archived from the original on 15 February 2022. Retrieved 7 February 2020.
    57. Gonzalez D, Bejarano I, Barriga C, Rodriguez AB, Pariente JA (2010). "Oxidative Stress-Induced Caspases are Regulated in Human Myeloid HL-60 Cells by Calcium Signal". Current Signal Transduction Therapy. 5 (2): 181–186. doi:10.2174/157436210791112172.
    58. Bejarano I, Espino J, González-Flores D, Casado JG, Redondo PC, Rosado JA, et al. (September 2009). "Role of Calcium Signals on Hydrogen Peroxide-Induced Apoptosis in Human Myeloid HL-60 Cells". International Journal of Biomedical Science. 5 (3): 246–256. PMC   3614781 . PMID   23675144.
    59. López-Lázaro M (July 2007). "Dual role of hydrogen peroxide in cancer: possible relevance to cancer chemoprevention and therapy". Cancer Letters. 252 (1): 1–8. doi:10.1016/j.canlet.2006.10.029. PMID   17150302.
    60. Rapoport R, Hanukoglu I, Sklan D (May 1994). "A fluorimetric assay for hydrogen peroxide, suitable for NAD(P)H-dependent superoxide generating redox systems". Analytical Biochemistry. 218 (2): 309–313. doi:10.1006/abio.1994.1183. PMID   8074285. S2CID   40487242. Archived from the original on 18 March 2020. Retrieved 1 July 2019.
    61. Tarr MA, ed. (2003). Chemical degradation methods for wastes and pollutants environmental and industrial applications. New York: M. Dekker. p. 165. ISBN   978-0-203-91255-3.
    62. Pignatello JJ, Oliveros E, MacKay A (January 2006). "Advanced Oxidation Processes for Organic Contaminant Destruction Based on the Fenton Reaction and Related Chemistry". Critical Reviews in Environmental Science and Technology. 36 (1): 1–84. doi:10.1080/10643380500326564. S2CID   93052585.
    63. Pera-Titus M, Garcıa-Molina V, Baños MA, Giménez J, Esplugas S (February 2004). "Degradation of chlorophenols by means of advanced oxidation processes: a general review". Applied Catalysis B: Environmental. 47 (4): 219–256. doi:10.1016/j.apcatb.2003.09.010.
    64. Goor G, Glenneberg J, Jacobi S (2007). "Hydrogen Peroxide". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a13_443.pub2. ISBN   978-3-527-30673-2.
    65. Ascenzi JM, ed. (1996). Handbook of disinfectants and antiseptics. New York: M. Dekker. p. 161. ISBN   978-0-8247-9524-5.
    66. Rutala WA, Weber DJ (September 2004). "Disinfection and sterilization in health care facilities: what clinicians need to know". Clinical Infectious Diseases. 39 (5): 702–709. doi: 10.1086/423182 . PMID   15356786.
    67. Falagas ME, Thomaidis PC, Kotsantis IK, Sgouros K, Samonis G, Karageorgopoulos DE (July 2011). "Airborne hydrogen peroxide for disinfection of the hospital environment and infection control: a systematic review". The Journal of Hospital Infection. 78 (3): 171–177. doi:10.1016/j.jhin.2010.12.006. PMID   21392848.
    68. Block SS, ed. (2000). "Chapter 9: Peroxygen compounds". Disinfection, sterilization, and preservation (5th ed.). Philadelphia: Lea & Febiger. pp. 185–204. ISBN   978-0-683-30740-5.
    69. 1 2 "Chemical Disinfectants | Disinfection & Sterilization Guidelines | Guidelines Library | Infection Control | CDC". www.cdc.gov. 4 April 2019. Archived from the original on 1 July 2017. Retrieved 12 April 2020.
    70. McDonnell G, Russell AD (January 1999). "Antiseptics and disinfectants: activity, action, and resistance". Clinical Microbiology Reviews. 12 (1): 147–179. doi:10.1128/cmr.12.1.147. PMC   88911 . PMID   9880479.
    71. Block SS, ed. (2000). "Chapter 27: Chemical Sporicidal and Sporostatic Agents". Disinfection, sterilization, and preservation (5th ed.). Philadelphia: Lea & Febiger. pp. 529–543. ISBN   978-0-683-30740-5.
    72. "Sec. 184.1366 Hydrogen peroxide". U.S. Government Printing Office via GPO Access. 1 April 2001. Archived from the original on 3 July 2007. Retrieved 7 July 2007.
    73. Wernimont EJ (9–12 July 2006). System Trade Parameter Comparison of Monopropellants: Hydrogen Peroxide vs Hydrazine and Others (PDF). 42nd AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit. Sacramento, California. Archived from the original (PDF) on 10 December 2014.
    74. Ventura M, Mullens P (19 June 1999). "The Use of Hydrogen Peroxide for Propulsion and Power" (PDF). General Kinetics, LLC. Archived from the original (PDF) on 10 December 2014. Retrieved 10 December 2014.
    75. Cieśliński D (2021). "Polish civil rockets' development overview". Archived from the original on 6 February 2022. Retrieved 15 February 2022.
    76. "Nucleus: A Very Different Way to Launch into Space". Nammo. Archived from the original on 6 February 2022. Retrieved 6 February 2022.
    77. "Peroxide Accident – Walter Web Site". Histarmar.com.ar. Archived from the original on 10 December 2014. Retrieved 14 February 2015.
    78. Scott R (November 1997). "Homing Instincts". Jane's Navy Steam Generated by Catalytic Decomposition of 80–90% Hydrogen Peroxide Was Used for Driving the Turbopump Turbines of the V-2 Rockets, the X-15 Rocketplanes, the Early Centaur RL-10 Engines and is Still Used on Soyuz for That Purpose Today. International. Archived from the original on 17 July 2011. Retrieved 12 May 2007.
    79. "Soyuz using hydrogen peroxide propellant". NASA . Archived from the original on 5 August 2013.
    80. Lane N (2003). Oxygen : the molecule that made the world (First issued in paperback, repr. ed.). Oxford: Oxford University Press. p. 117. ISBN   978-0-19-860783-0. Archived from the original on 13 April 2021. Retrieved 12 November 2020.
    81. Sulieman M, Addy M, MacDonald E, Rees JS (May 2004). "The effect of hydrogen peroxide concentration on the outcome of tooth whitening: an in vitro study". Journal of Dentistry. Elsevier Ltd. 32 (4): 295–299. doi:10.1016/j.jdent.2004.01.003. PMID   15053912. Archived from the original on 15 February 2022. Retrieved 30 September 2021.
    82. Shepherd S. "Brushing Up on Gum Disease". FDA Consumer. Archived from the original on 14 May 2007. Retrieved 7 July 2007.
    83. Gibbs KB (14 November 2016). "How to remove blood stains from clothes and furniture". Today.com. Archived from the original on 20 May 2021. Retrieved 5 August 2021.
    84. Mayntz M. "Dried Blood Stain Removal". Lovetoknow.com. Archived from the original on 17 August 2021. Retrieved 5 August 2021.
    85. Capizzi R, Landi F, Milani M, Amerio P (August 2004). "Skin tolerability and efficacy of combination therapy with hydrogen peroxide stabilized cream and adapalene gel in comparison with benzoyl peroxide cream and adapalene gel in common acne. A randomized, investigator-masked, controlled trial". The British Journal of Dermatology. 151 (2): 481–484. doi:10.1111/j.1365-2133.2004.06067.x. PMID   15327558. S2CID   2611939.
    86. "Ways to use Hydrogen Peroxide in the Garden". Using Hydrogen Peroxide. Archived from the original on 4 March 2016. Retrieved 3 March 2016.
    87. Bhattarai SP, Su N, Midmore DJ (2005). Oxygation Unlocks Yield Potentials of Crops in Oxygen-Limited Soil Environments. Advances in Agronomy. Vol. 88. pp. 313–377. doi:10.1016/S0065-2113(05)88008-3. ISBN   978-0-12-000786-8.
    88. "Hydrogen Peroxide for Plants and Garden". 7 September 2019. Archived from the original on 10 May 2021. Retrieved 10 May 2021.
    89. "Effect of hydrogen peroxide spraying on Hydrocotyle ranunculoides". Archived from the original on 24 March 2020. Retrieved 10 May 2021.
    90. "FDA Approves Additional Indications for 35% PEROX-AID (hydrogen peroxide) for Use in Certain Finfish". FDA. 26 July 2019. Archived from the original on 12 December 2019. Retrieved 19 December 2019.
    91. Greene B, Baker D, Frazier W. "Hydrogen Peroxide Accidents and Incidents: What we can learn from history" (PDF). NASA. Archived (PDF) from the original on 6 April 2019. Retrieved 6 April 2019.
    92. see Hans Marquardt, Lehrbuch der Toxikologie
    93. "Material Compatibility with Hydrogen Peroxide". Archived from the original on 4 March 2016. Retrieved 3 March 2016.
    94. "Hydrogen Peroxide Mouthwash is it Safe?". Archived from the original on 20 December 2013. Retrieved 30 October 2013.
    95. 1 2 3 "Occupational Safety and Health Guideline for Hydrogen Peroxide". Archived from the original on 13 May 2013.
    96. For example, see an MSDS for a 3% peroxide solution Archived 15 April 2012 at the Wayback Machine .
    97. H2O2 toxicity and dangers Archived 5 June 2012 at the Wayback Machine Agency for Toxic Substances and Disease Registry website
    98. CRC Handbook of Chemistry and Physics, 76th Ed, 1995–1996
    99. "CDC – Immediately Dangerous to Life or Health Concentrations (IDLH): Chemical Listing and Documentation of Revised IDLH Values – NIOSH Publications and Products". 25 October 2017. Archived from the original on 17 November 2012. Retrieved 20 October 2018.
    100. "Threshold Limit Values for Chemical Substances and Physical Agents & Biological Exposure Indices, ACGIH" (PDF). Archived from the original (PDF) on 2 June 2013.
    101. "ATSDR – Redirect – MMG: Hydrogen Peroxide". Archived from the original on 3 March 2016. Retrieved 3 March 2016.
    102. Wilgus TA, Bergdall VK, Dipietro LA, Oberyszyn TM (2005). "Hydrogen peroxide disrupts scarless fetal wound repair". Wound Repair and Regeneration. 13 (5): 513–519. doi:10.1111/j.1067-1927.2005.00072.x. PMID   16176460. S2CID   1028923.
    103. Urban MV, Rath T, Radtke C (June 2019). "Hydrogen peroxide (H2O2): a review of its use in surgery". Wiener Medizinische Wochenschrift. 169 (9–10): 222–225. doi:10.1007/s10354-017-0610-2. PMID   29147868. S2CID   35739209.
    104. "Cleveleand Clinic: What Is Hydrogen Peroxide Good For?". December 2021. Retrieved 25 August 2022.{{cite web}}: CS1 maint: url-status (link)
    105. see e.g. Detlev Heidemann, Endodontie, Urban&Fischer 2001
    106. Douglass WC (1995). Hydrogen peroxide : medical miracle. Atlanta, GA: Second Opinion Pub. ISBN   978-1-885236-07-4.
    107. 1 2 Hydrogen Peroxide, 3%. 3. Hazards Identification Southeast Fisheries Science Center, daughter agency of NOAA.
    108. 1 2 "Questionable methods of cancer management: hydrogen peroxide and other 'hyperoxygenation' therapies". CA: A Cancer Journal for Clinicians. 43 (1): 47–56. 1993. doi: 10.3322/canjclin.43.1.47 . PMID   8422605. S2CID   36911297.
    109. 1 2 Cooper A (12 January 2005). "A Prescription for Death?". CBS News. Archived from the original on 17 July 2007. Retrieved 7 July 2007.
    110. 1 2 Mikkelson B (30 April 2006). "Hydrogen Peroxide". Snopes.com. Archived from the original on 15 February 2022. Retrieved 7 July 2007.
    111. 1 2 "Naturopath Sentenced For Injecting Teen With Hydrogen Peroxide – 7NEWS Denver". Thedenverchannel.com. 27 March 2006. Archived from the original on 20 March 2014. Retrieved 14 February 2015.
    112. Halliwell B (January 2007). "Oxidative stress and cancer: have we moved forward?". The Biochemical Journal. 401 (1): 1–11. doi:10.1042/BJ20061131. PMID   17150040. S2CID   850978. Archived from the original on 15 February 2022. Retrieved 30 November 2019.
    113. French LK, Horowitz BZ, McKeown NJ (July 2010). "Hydrogen peroxide ingestion associated with portal venous gas and treatment with hyperbaric oxygen: a case series and review of the literature". Clinical Toxicology. 48 (6): 533–538. doi:10.3109/15563650.2010.492526. PMID   20575671. S2CID   25148041. Archived from the original on 4 January 2022. Retrieved 4 January 2022.
    114. "Heeresversuchsstelle Kummersdorf". UrbEx | Forgotten & Abandoned. 23 March 2008. Archived from the original on 29 June 2018. Retrieved 1 June 2018.
    115. "The Nazi Doctors: Medical Killing and the Psychology of Genocide". Robert Jay Lifton. Archived from the original on 27 June 2018. Retrieved 26 June 2018.
    116. "Explosion and fire in a hydrogen peroxide plant". ARIA. November 2007. Archived from the original on 14 February 2022.
    117. "Accident No: DCA-99-MZ-001" (PDF). U.S. National Transportation Safety Board. Archived (PDF) from the original on 3 November 2015. Retrieved 30 October 2015.
    118. Mizokami K (28 September 2018). "The True Story of the Russian Kursk Submarine Disaster". Archived from the original on 14 February 2022.
    119. Wheaton S (16 August 2010). "Bleach Spill Shuts Part of Times Square". The New York Times. Archived from the original on 1 December 2017. Retrieved 24 February 2017.