Phosphorus acid

Phosphorus oxoacids are oxoacids of phosphorus. Phosphorus exhibits oxidation states from +1 to +5. Oxygen may be in oxidation state -2 or -1, depending on whether a compound contains the peroxide group.

There are a large number of such compounds, some of which cannot be isolated and are only known through their salts.

Examples of phosphorus acids include:^[1]

Phosphorus oxoacids containing P in oxidation state +1:

*H3PO2 (or H2PO(OH)), Hypophosphorous acid or phosphinic acid, a monoprotic acid

Phosphorus oxoacids containing P in oxidation state +3:

*H3PO3 (or HPO(OH)2), Phosphorous acid or phosphonic acid, a diprotic acid

Phosphorus oxoacids containing P in oxidation state +5 (see also phosphoric acids and phosphates):

*H3PO4 (or PO(OH)3), Phosphoric acid, a tribasic acid

• • A similar compound is peroxomonophosphoric acid H₃PO₅ (or OP(OH)₂(OOH)), a tribasic acid containing a peroxide group that replaces an oxygen atom in the hydroxyl group

*H4P2O7 (or (OH)2(O)P-O-P(O)(OH)2), Pyrophosphoric acid, a tetraprotic acid
*H5P3O10 (or (OH)2(O)P-O-P(O)(OH)-O-P(O)(OH)2), Triphosphoric acid, a pentaprotic acid
*H3P3O9 (or (HPO3)3, (P(O)(OH)-O-)3),  Trimetaphosphoric acid, a triprotic acid

Phosphorus oxoacids containing P in oxidation state +4:

*H4P2O6 (or (OH)2P(O)−P(O)(OH)2), Hypophosphoric acid, a tetraprotic acid

Phosphorus oxoacids containing P in mixed oxidation states:

*H4P2O6 (or H(OH)(O)P-O-P(O)(OH)2), Isohypophosphoric acid, a tetraprotic acid and isomer of hypophosphoric acid, containing P in oxidation state +3 and +5

External links

• Phosphorus Acids at the US National Library of Medicine Medical Subject Headings (MeSH)

References

1. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 0-08-037941-9.