Calcium monophosphide
Introduction '''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 (Na2O2) are very similar. The solid is described as a salt: (Ca2+)2P24−, or Ca2P2.Since the bonding is ionic, the diphosphide centers carry negative charge and are easily protonated. Upon hydrolysis this material releases diphosphine (P2H4)::Ca2P2  +  4 H2O   →   2 Ca(OH)2  +  P2H4The hydrolyses of CaP and calcium carbide (CaC2) are similar, except that diphosphine spontaneously ignites in air. Thus, CaP must be protected from air.CaP decomposes to Ca3P2 at about 600 °C. :3 CaP   →   Ca3P2  +  1/4 P4
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