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