Editing Polyphosphate (section)

==Formation and synthesis==
Polyphosphates arise by polymerization of phosphoric acid derivatives. The process begins with two phosphate units coming together in a condensation reaction. 
:2 H(PO<sub>4</sub>)<sup>2&minus;</sup>   {{eqm}}   (P<sub>2</sub>O<sub>7</sub>)<sup>4&minus;</sup> + H<sub>2</sub>O
The condensation is shown as an [[chemical equilibrium|equilibrium]] because the reverse reaction, [[hydrolysis]], is also possible. The process may continue in steps; at each step another (PO<sub>3</sub>)<sup>&minus;</sup> unit is added to the chain, as indicated by the part in brackets in the illustration of polyphosphoric acid. P<sub>4</sub>O<sub>10</sub> can be seen as the end product of condensation reactions, where each tetrahedron shares three corners with the others. Conversely, a complex mix of polymers is produced when a small amount of water is added to phosphorus pentoxide.