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Names | |
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IUPAC name Lead(II) acetate | |
Systematic IUPAC name Lead(II) ethanoate | |
Other names | |
Identifiers | |
3D model (JSmol) | |
ChEBI | |
ChEMBL | |
ChemSpider | |
ECHA InfoCard | 100.005.551 |
EC Number |
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MeSH | lead+acetate |
PubChem CID | |
RTECS number |
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UNII |
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CompTox Dashboard (EPA) | |
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Properties | |
Pb(C2H3O2)2 | |
Molar mass | 325.29 g/mol (anhydrous) 379.33g/mol (trihydrate) |
Appearance | White powder or colourless, efflorescent crystals |
Odor | Slightly acetic |
Density | 3.25 g/cm3 (20 °C, anhydrous) 2.55 g/cm3 (trihydrate) 1.69 g/cm3 (decahydrate) [1] |
Melting point | 280 °C (536 °F; 553 K) (anhydrous) 75 °C (167 °F; 348 K) (trihydrate) decomposes [2] at ≥ 200 °C 22 °C (72 °F; 295 K) (decahydrate) [1] |
Boiling point | Decomposes |
Anhydrous: 19.8 g/100 mL (0 °C) 44.31 g/100 mL (20 °C) 69.5 g/100 mL (30 °C) [3] 218.3 g/100 mL (50 °C) [1] | |
Solubility | Anhydrous and trihydrate are soluble in alcohol, glycerol [3] |
Solubility in methanol | Anhydrous: [3] 102.75 g/100 g (66.1 °C) Trihydrate: [4] 74.75 g/100 g (15 °C) 214.95 g/100 g (66.1 °C) |
Solubility in glycerol | Anhydrous: [3] 20 g/100 g (15 °C) Trihydrate: [4] 143 g/100 g (20 °C) |
−89.1·10−6 cm3/mol | |
Refractive index (nD) | 1.567 (trihydrate) [1] |
Structure | |
Monoclinic (anhydrous, trihydrate) Rhombic (decahydrate) | |
Thermochemistry | |
Std enthalpy of formation (ΔfH⦵298) | −960.9 kJ/mol (anhydrous) [3] −1848.6 kJ/mol (trihydrate) [4] |
Hazards | |
Occupational safety and health (OHS/OSH): | |
Main hazards | Neurotoxic, probable human carcinogen |
GHS labelling: | |
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Danger | |
H360, H373, H410 [2] | |
P201, P273, P308+P313, P501 [2] | |
NFPA 704 (fire diamond) | |
Flash point | Non-flammable |
Lethal dose or concentration (LD, LC): | |
LD50 (median dose) | 400 mg/kg (mice, oral) [1] |
LCLo (lowest published) | 300 mg/kg (dog, oral) [5] |
Related compounds | |
Other cations | Lead(IV) acetate |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Lead(II) acetate is a white crystalline chemical compound with a slightly sweet taste. Its chemical formula is usually expressed as Pb(CH3COO)2 or Pb(OAc)2, where Ac represents the acetyl group. Like many other lead compounds, it causes lead poisoning. Lead acetate is soluble in water and glycerin. With water it forms the trihydrate, Pb(OAc)2·3H2O, a colourless or white efflorescent monoclinic crystalline substance.
The substance is used as a reagent to make other lead compounds and as a fixative for some dyes. In low concentrations, it formerly served as the principal active ingredient in progressive types of hair colouring dyes. [6] Lead(II) acetate is also used as a mordant in textile printing and dyeing, and as a drier in paints and varnishes. It was historically used as a sweetener and preservative in wines and in other foods and for cosmetics.
Lead(II) acetate can be made by boiling elemental lead in acetic acid and hydrogen peroxide. This method will also work with lead(II) carbonate or lead(II) oxide.
Lead(II) acetate can also be made by dissolving lead(II) oxide in acetic acid: [7]
Lead(II) acetate can also be made via a single displacement reaction between copper acetate and lead metal:
The crystal structure of anhydrous lead(II) acetate has been described as a 2D coordination polymer. In comparison, lead(II) acetate trihydrate's structure is a 1D coordination polymer. [8] In the trihydrate, the Pb2+ ion's coordination sphere consists of nine oxygen atoms belonging to three water molecules, two bidentate acetate groups and two bridging acetate groups. The coordination geometry at Pb is a monocapped square antiprism. [9] [10] The trihydrate thermally decomposes to a hemihydrate, Pb(OAc)2·1⁄2H2O, and to basic acetates such as Pb4O(OAc)6 and Pb2O(OAc)2. [8]
Anhydrous [8] Pb(OAc)2 | Trihydrate [9] [10] Pb(OAc)2·3H2O | |
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Lead coordination sphere | ![]() | ![]() |
Strongly bonded aggregation | ![]() 2D sheet | ![]() 1D chain |
Weakly bonded aggregation | ![]() sheets stacked with hydrophobic surfaces in contact | ![]() chains linked by hydrogen bonds |
Lead acetate is used as a precursor to other lead compounds such as the various carbonate.
Lead(II) acetate paper is used to detect the poisonous gas hydrogen sulfide. The gas reacts with lead(II) acetate on the moistened test paper to form a grey precipitate of lead(II) sulfide.
An aqueous solution of lead(II) acetate is a byproduct of the process used in the cleaning and maintenance of stainless steel firearm suppressors (silencers) and compensators when using a 1:1 ratio of hydrogen peroxide and white vinegar (acetic acid). The solution is agitated by the bubbling action of the hydrogen peroxide, with the main reaction being the oxidation of lead by hydrogen peroxide and subsequent dissolution of lead oxide by the acetic acid, which forms lead acetate. Because of its high toxicity, this chemical solution must be appropriately disposed by a chemical processing facility or hazardous materials centre. Alternatively, the solution may be reacted with sulfuric acid to precipitate nearly insoluble lead(II) sulfate. The solid may then be removed by mechanical filtration and is safer to dispose of than aqueous lead acetate.
Like other lead(II) salts, lead(II) acetate has a sweet taste, which led to its historical use as a sugar substitute in both wines and foods. [11] The ancient Romans, who had few sweeteners besides honey, would boil must (unfiltered grape juice) in lead pots to produce a reduced sugar syrup called defrutum , concentrated again into sapa . This syrup was used to sweeten wine and to sweeten and preserve fruit. It is possible that lead(II) acetate or other lead compounds leaching into the syrup might have caused lead poisoning in those who consumed it. [12] Lead acetate is no longer used in the production of sweeteners because of its recognized toxicity. Legislation prohibiting its use as a wine sweetener was ineffective until decades later, when chemical methods of detecting its presence had been developed. [13]
The earliest confirmed poisoning by lead acetate was that of Pope Clement II, who died in October 1047. A toxicological examination of his remains conducted in the mid-20th century confirmed centuries-old rumors that he had been poisoned with lead sugar. [14] It is not clear whether he was assassinated.
In 1787 painter and biographer Albert Christoph Dies swallowed, by accident, approximately 3/4 oz (20 g) of lead acetate. His recovery from this poison was slow and incomplete. He lived with illnesses until his death in 1822. [15] [16]
Although the use of lead(II) acetate as a sweetener was already illegal at that time, composer Ludwig van Beethoven may have died of lead poisoning caused by wines adulterated with lead acetate (see also Beethoven's liver). [17] [18]
In 1887, 38 hunting horses belonging to Captain William Hollwey Steeds were poisoned in their stables at Clonsilla House, Dublin, Ireland. At least ten of the hunters died. Captain Steeds, an "extensive commission agent", had previously supplied the horses for the Bray and Greystones Coach. It transpired that they had been fed a bran mash that had been sweetened with a toxic lead acetate. [19]
Lead(II) acetate, as well as white lead, has been used in cosmetics throughout history. [20]
It was once used for men's hair colouring products [21] like Grecian Formula. It was not until 2018 that the manufacturer removed lead acetate from the hair coloring product. Lead acetate has been replaced by bismuth citrate as the progressive colorant. Its use in cosmetics has been banned in Canada by Health Canada since 2005 (effective at the end of 2006) based on tests showing possible carcinogenicity and reproductive toxicity, [22] and it is also banned in the European Union. [22]
Lead(II) acetate solution was a commonly used folk remedy for sore nipples. [23] In modern medicine, for a time, it was used as an astringent, in the form of Goulard's extract, and it has also been used to treat poison ivy. [24]
In the 1850s, Mary Seacole applied lead(II) acetate, among other remedies, against an epidemic of cholera in Panama. [25] [26]
It was also used in making of slow matches during the Middle Ages. It was made by mixing a natural form of lead(II) oxide called litharge and vinegar.
Sugar of lead was a recommended agent added to linseed oil during heating to produce "boiled" linseed oil, the lead and heat acting to cause the oil to cure faster than raw linseed oil. [27]
Lead(II) acetate ("salt of Saturn") was used to synthesise acetone which was then known as "spirit of Saturn" for being made with the salt of Saturn and thought to be a lead compound in the 17th century. [28]
An acetate is a salt formed by the combination of acetic acid with a base. "Acetate" also describes the conjugate base or ion typically found in aqueous solution and written with the chemical formula C
2H
3O−
2. The neutral molecules formed by the combination of the acetate ion and a positive ion are also commonly called "acetates". The simplest of these is hydrogen acetate with corresponding salts, esters, and the polyatomic anion CH
3CO−
2, or CH
3COO−
.
Hair coloring, or hair dyeing, is the practice of changing the color of the hair on humans' heads. The main reasons for this are cosmetic: to cover gray or white hair, to alter hair to create a specific look, to change a color to suit preference or to restore the original hair color after it has been discolored by hairdressing processes or sun bleaching.
Lead(II) sulfide is an inorganic compound with the formula PbS. Galena is the principal ore and the most important compound of lead. It is a semiconducting material with niche uses.
Lead(II) oxide, also called lead monoxide, is the inorganic compound with the molecular formula PbO. PbO occurs in two polymorphs: litharge having a tetragonal crystal structure, and massicot having an orthorhombic crystal structure. Modern applications for PbO are mostly in lead-based industrial glass and industrial ceramics, including computer components. It is an amphoteric oxide.
Lead(II) chloride (PbCl2) is an inorganic compound which is a white solid under ambient conditions. It is poorly soluble in water. Lead(II) chloride is one of the most important lead-based reagents. It also occurs naturally in the form of the mineral cotunnite.
Classical qualitative inorganic analysis is a method of analytical chemistry which seeks to find the elemental composition of inorganic compounds. It is mainly focused on detecting ions in an aqueous solution, therefore materials in other forms may need to be brought to this state before using standard methods. The solution is then treated with various reagents to test for reactions characteristic of certain ions, which may cause color change, precipitation and other visible changes.
Sodium acetate, CH3COONa, also abbreviated NaOAc, is the sodium salt of acetic acid. This salt is colorless deliquescent, and Hygroscopic.
Lead(II,IV) oxide, also called red lead or minium, is the inorganic compound with the formula Pb3O4. A bright red or orange solid, it is used as pigment, in the manufacture of batteries, and rustproof primer paints. It is an example of a mixed valence compound, being composed of both Pb(II) and Pb(IV) in the ratio of two to one.
Lead(IV) oxide, commonly known as lead dioxide, is an inorganic compound with the chemical formula PbO2. It is an oxide where lead is in an oxidation state of +4. It is a dark-brown solid which is insoluble in water. It exists in two crystalline forms. It has several important applications in electrochemistry, in particular as the positive plate of lead acid batteries.
Lead(II) hydroxide, Pb(OH)2, is a hydroxide of lead, with lead in oxidation state +2.
Mercury(II) acetate, also known as mercuric acetate is a chemical compound, the mercury(II) salt of acetic acid, with the formula Hg(O2CCH3)2. Commonly abbreviated Hg(OAc)2, this compound is employed as a reagent to generate organomercury compounds from unsaturated organic precursors. It is a white, water-soluble solid, but some samples can appear yellowish with time owing to decomposition.
Organolead chemistry is the scientific study of the synthesis and properties of organolead compounds, which are organometallic compounds containing a chemical bond between carbon and lead. The first organolead compound was hexaethyldilead (Pb2(C2H5)6), first synthesized in 1858. Sharing the same group with carbon, lead is tetravalent.
Lead(IV) acetate or lead tetraacetate is an metalorganic compound with chemical formula Pb(C2H3O2)4. It is a colorless solid that is soluble in nonpolar, organic solvents, indicating that it is not a salt. It is degraded by moisture and is typically stored with additional acetic acid. The compound is used in organic synthesis.
Ferric acetate is the iron compound with the formula Fe3O(O2CCH3)6(H2O)3]O2CCH3. This red brown solid is the acetate salt of the coordination complex [Fe3O(OAc)6(H2O)3]+ (OAc− is CH3CO2−). Commonly, the salt is known as "basic iron acetate". The formation of the red-brown complex was once used as a test for ferric ions.
White lead is the basic lead carbonate 2PbCO3·Pb(OH)2. It is a complex salt, containing both carbonate and hydroxide ions. White lead occurs naturally as a mineral, in which context it is known as hydrocerussite, a hydrate of cerussite. It was formerly used as an ingredient for lead paint and a cosmetic called Venetian ceruse, because of its opacity and the satiny smooth mixture it made with dryable oils. However, it tended to cause lead poisoning, and its use has been banned in most countries.
Acetic acid, systematically named ethanoic acid, is an acidic, colourless liquid and organic compound with the chemical formula CH3COOH. Vinegar is at least 4% acetic acid by volume, making acetic acid the main component of vinegar apart from water. It has been used, as a component of vinegar, throughout history from at least the third century BC.
Lead(II) thiocyanate is a compound, more precisely a salt, with the formula Pb(SCN)2. It is a white crystalline solid, but will turn yellow upon exposure to light. It is slightly soluble in water and can be converted to a basic salt (Pb(CNS)2·Pb(OH)2 when boiled. Salt crystals may form upon cooling. Lead thiocyanate can cause lead poisoning if ingested and can adversely react with many substances. It has use in small explosives, matches, and dyeing.
Anhydrous magnesium acetate has the chemical formula Mg(C2H3O2)2 and in its hydrated form, magnesium acetate tetrahydrate, it has the chemical formula Mg(CH3COO)2 • 4H2O. In this compound magnesium has an oxidation state of 2+. Magnesium acetate is the magnesium salt of acetic acid. It is deliquescent and upon heating, it decomposes to form magnesium oxide. Magnesium acetate is commonly used as a source of magnesium in biological reactions.
Compounds of lead exist with lead in two main oxidation states: +2 and +4. The former is more common. Inorganic lead(IV) compounds are typically strong oxidants or exist only in highly acidic solutions.
Aluminium triacetate, formally named aluminium acetate, is a chemical compound with composition Al(CH
3CO
2)
3. Under standard conditions it appears as a white, water-soluble solid that decomposes on heating at around 200 °C. The triacetate hydrolyses to a mixture of basic hydroxide / acetate salts, and multiple species co-exist in chemical equilibrium, particularly in aqueous solutions of the acetate ion; the name aluminium acetate is commonly used for this mixed system.
From the results achieved so far it is obvious that the purity law for lead in wines in the last two centuries was frequently ignored.