Selenophosphate

A selenophosphate is a chemical compound containing phosphate anions substituted with selenium. Over 7000 compounds are known with a bond between selenium and phosphorus. Compared to phosphorus-sulfur compounds selenophosphates are less thermally stable, and more easily destroyed by water. However they are more stable than tellurophosphates which have an even weaker phosphorus-tellurium bond. Selenophosphates have an oxidation number for phosphorus of +5. But in many there are bonds between phosphorus atoms, reducing the oxidation state to +4, Some may be termed selenophosphites.

Different structural anions include hexaselenohypodiphosphate [P₂Se₆]⁴⁻ and [P₆Se₁₂]⁴⁻ with decalin structure and [P₄Se₂]²⁻ with dicyclobutane structure.

Selenophosphates are coloured, often orange. They are semiconductors.

The first selenodiphosphate was discovered in 1973 by H. Hahn.

Selenophosphate compounds may have some or all of the selenium replaced by sulfur.