Calcium monophosphide

Calcium monophosphide is the inorganic compound with the formula CaP. It is sometimes also known as "calcium phosphide", which also describes a different compound with composition Ca₃P₂. Calcium monophosphide is a black solid.

Structure and properties

The structures of CaP and sodium peroxide are very similar. The solid is described as a salt: ₂P₂⁴⁻, or Ca₂P₂. Since the bonding is ionic, the diphosphide centers carry negative charge and are easily protonated. Upon hydrolysis this material releases diphosphine :
The hydrolyses of CaP and calcium carbide are similar, except that diphosphine spontaneously ignites in air. Thus, CaP must be protected from air.
CaP decomposes to Ca₃P₂ at about 600 °C.