Phosphorus forms a number of oxoacids as given in below table.
Oxoacids of phosphorus
|Name||Formula||Oxidation state of P|
|Diphosphoric acid (Pyrophosphoric acid)||H4P2O7||+5|
Among the oxoacids of phosphorus, orthophosphoric acid is the most important and is used in the manufacture of phosphate fertilizers.
The structures of oxoacids of phosphorus are systematically given ahead:
The formulae of oxoacids of P can be remembered as:
a) meta acid is used for the acid obtained by the loss of one water molecule.
b) pyro acid is used for the acid obtained by heating two molecules with loss of one water molecule.
c) hypo is generally used for the acid having lower oxygen content than the parent acid.
However. it may be noted that metaphosphoric acid does not exist as simple monomer; it exists are cyclometaphosphoric acid or polymetaphosphoric acid.