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Names | |
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Other names peroxodiphosphoric acid | |
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CompTox Dashboard (EPA) | |
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Properties | |
H4P2O8 | |
Molar mass | 193.97 g/mol |
Related compounds | |
Related compounds | peroxymonophosphoric acid |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Peroxydiphosphoric acid ((HO2P(O)O−OP(O)(OH)2) is an oxyacid of phosphorus. Its salts are known as peroxydiphosphates. It is closely related to peroxymonophosphoric acid. These compounds (and their salts) are in turn related to the peroxydisulfuric acid and peroxysulfuric acid. These compounds are all colorless. [1] In terms of structure, peroxydiphosphoric acid features two tetrahedral phosphorus centers linked by a peroxide group.
Both peroxyphosphoric acids were first synthesized and characterized in 1910 by Julius Schmidlin and Paul Massini, [2] where peroxydiphosphoric acid was obtained in poor yields from the reaction between diphosphoric acid and highly-concentrated hydrogen peroxide.
Peroxydiphosphoric acid can be prepared by the reaction between phosphoric acid and fluorine, with peroxymonophosphoric acid being a by-product. [1]
The compound is not commercially available and must be prepared as needed. [1] Potassium peroxodiphosphate, which is commercially available, can be obtained by electrolysis of phosphate solutions. [3] [1]
Peroxydiphosphoric acid is a tetraprotic acid, with acid dissociation constants given by pKa1 ≈ −0.3, pKa2 ≈ 0.5, pKa3 = 5.2 and pKa4 = 7.6. [4] In aqueous solution, it disproportionates upon heating to peroxymonophosphoric acid and phosphoric acid. [5]
Phosphoric acid is a colorless, odorless phosphorus-containing solid, and inorganic compound with the chemical formula H3PO4. It is commonly encountered as an 85% aqueous solution, which is a colourless, odourless, and non-volatile syrupy liquid. It is a major industrial chemical, being a component of many fertilizers.
Pyrophosphoric acid, also known as diphosphoric acid, is the inorganic compound with the formula H4P2O7 or, more descriptively, [(HO)2P(O)]2O. Colorless and odorless, it is soluble in water, diethyl ether, and ethyl alcohol. The anhydrous acid crystallizes in two polymorphs, which melt at 54.3 and 71.5 °C. The compound is a component of polyphosphoric acid, an important source of phosphoric acid. Anions, salts, and esters of pyrophosphoric acid are called pyrophosphates.
Phosphorus pentachloride is the chemical compound with the formula PCl5. It is one of the most important phosphorus chlorides/oxychlorides, others being PCl3 and POCl3. PCl5 finds use as a chlorinating reagent. It is a colourless, water-sensitive solid, although commercial samples can be yellowish and contaminated with hydrogen chloride.
Peroxymonosulfuric acid, also known as persulfuric acid, peroxysulfuric acid is the inorganic compound with the formula H2SO5. It is a white solid. It is a component of Caro's acid, which is a solution of peroxymonosulfuric acid in sulfuric acid containing small amounts of water. Peroxymonosulfuric acid is a very strong oxidant.
Phosphorous acid is the compound described by the formula H3PO3. This acid is diprotic, not triprotic as might be suggested by this formula. Phosphorous acid is an intermediate in the preparation of other phosphorus compounds. Organic derivatives of phosphorous acid, compounds with the formula RPO3H2, are called phosphonic acids.
In chemistry, a phosphoric acid, in the general sense, is a phosphorus oxoacid in which each phosphorus (P) atom is in the oxidation state +5, and is bonded to four oxygen (O) atoms, one of them through a double bond, arranged as the corners of a tetrahedron. Two or more of these PO4 tetrahedra may be connected by shared single-bonded oxygens, forming linear or branched chains, cycles, or more complex structures. The single-bonded oxygen atoms that are not shared are completed with acidic hydrogen atoms. The general formula of a phosphoric acid is Hn+2−2xPnO3n+1−x, where n is the number of phosphorus atoms and x is the number of fundamental cycles in the molecule's structure, between 0 and n + 2/2.
Hypophosphorous acid (HPA), or phosphinic acid, is a phosphorus oxyacid and a powerful reducing agent with molecular formula H3PO2. It is a colorless low-melting compound, which is soluble in water, dioxane and alcohols. The formula for this acid is generally written H3PO2, but a more descriptive presentation is HOP(O)H2, which highlights its monoprotic character. Salts derived from this acid are called hypophosphites.
Sodium trimetaphosphate (also STMP), with formula Na3P3O9, is one of the metaphosphates of sodium. It has the formula Na3P3O9 but the hexahydrate Na3P3O9·(H2O)6 is also well known. It is the sodium salt of trimetaphosphoric acid. It is a colourless solid that finds specialised applications in food and construction industries: it is used as a phosphorylating agent for ascorbic acid to stabilize vitamin C mixtures against thermal decomposition; in the construction industry, sodium trimetaphosphate is used to prevent the shrinkage of gypsum plaster boards (US Pat. 03/0154888) and as a setting retarder for gypsum plaster.
Potassium hypomanganate is the inorganic compound with the formula K3MnO4. Also known as potassium manganate(V), this bright blue solid is a rare example of a salt with the hypomanganate or manganate(V) anion, where the manganese atom is in the +5 oxidation state. It is an intermediate in the production of potassium permanganate and the industrially most important Mn(V) compound.
Fluoroboric acid or tetrafluoroboric acid is an inorganic compound with the simplified chemical formula H+[BF4]−. Solvent-free tetrafluoroboric acid has not been reported. The term "fluoroboric acid" usually refers to a range of compounds including hydronium tetrafluoroborate, which are available as solutions. The ethyl ether solvate is also commercially available, where the fluoroboric acid can be represented by the formula [H( 2O)n]+[BF4]−, where n is 2.
Thiophosphoryl chloride is an inorganic compound with the chemical formula PSCl3. It is a colorless pungent smelling liquid that fumes in air. It is synthesized from phosphorus chloride and used to thiophosphorylate organic compounds, such as to produce insecticides.
Ethenone is the formal name for ketene, an organic compound with formula C2H2O or H2C=C=O. It is the simplest member of the ketene class. It is an important reagent for acetylations.
Thiophosphates (or phosphorothioates, PS) are chemical compounds and anions with the general chemical formula PS
4−xO3−
x (x = 0, 1, 2, or 3) and related derivatives where organic groups are attached to one or more O or S. Thiophosphates feature tetrahedral phosphorus(V) centers.
Copper(II) phosphate are inorganic compounds with the formula Cu3(PO4)2. They can be regarded as the cupric salts of phosphoric acid. Anhydrous copper(II) phosphate and a trihydrate are blue solids.
Phosphoryl fluoride is a compound with the chemical formula POF3. It is a colorless gas that hydrolyzes rapidly. It has a critical temperature of 73 °C and a critical pressure of 4.25 bars.
Difluorophosphate or difluorodioxophosphate or phosphorodifluoridate is an anion with formula PO2F−2. It has a single negative charge and resembles perchlorate and monofluorosulfonate in shape and compounds. These ions are isoelectronic, along with tetrafluoroaluminate, phosphate, orthosilicate, and sulfate. It forms a series of compounds. The ion is toxic to mammals as it causes blockage to iodine uptake in the thyroid. However it is degraded in the body over several hours.
Phosphoramides are a class of phosphorus compounds with the formula O=P(NR2)3-n(OH)n. They can be considered derivatives of phosphoric acid where OH groups have been replaced with an amino or R-substituted amino group. In practise the term is commonly confined to the phosphoric triamides (P(=O)(NR2)3), essentially phosphoramide and derivatives thereof. Derivatives with the general structures P(=O)(OH)(NR2)2 or P(=O)(OH)2(NR2) are usually referred to as phosphoramidic acids.
Phosphoric chloride difluoride POF2Cl is a colourless gas. At one atmosphere pressure the gas condenses to a liquid at 3.1 °C and freezes at −96.4. Alternate names are difluorophosphoryl chloride or phosphoryl chloride difluoride.
Difluorophosphoric acid is an inorganic compound with the formula HPO2F2. It is a mobile colorless strongly fuming liquid. The acid has limited applications, in part because it is thermally and hydrolytically unstable. Difluorophosphoric acid is corrosive to glass, fabric, metals and living tissue.
Peroxymonophosphoric acid is an oxyacid of phosphorus. It is a colorless viscous oil. Its salts are called peroxymonophosphates. Another peroxyphosphoric acid is peroxydiphosphoric acid, H4P2O8.