Ca3P2

Ca3P2, commonly referred to as calcium phosphide, is an inorganic binary compound of calcium and phosphorus. Its formula reflects an ionic lattice composed of Ca2+ cations and P3− anions, placing it within the family of metal phosphides.

Ca3P2 is a white to pale gray crystalline solid with a high melting point. It is insoluble in water, but reacts with moisture to release phosphine gas (PH3). In dry air it is relatively stable, although it may slowly form surface oxides or phosphates upon exposure over time.

Preparation typically involves high-temperature synthesis. Ca3P2 can be produced by direct reaction of elemental calcium with phosphorus under inert atmosphere. It can also be obtained by the reduction of calcium phosphate sources with carbon or silicon-containing reagents at elevated temperatures.

Chemical behavior and applications: A characteristic reaction is Ca3P2 + 6 H2O → 3 Ca(OH)2 + 2 PH3, illustrating its hydrolysis to give phosphine, a toxic and flammable gas. Due to this property, handling requires stringent controls. Calcium phosphide has historically been used as a source of phosphine for fumigation and as a precursor in the preparation of other phosphorus-containing compounds. In laboratory settings it serves as a phosphorus source for various syntheses and the preparation of phosphide materials.

Safety: Phosphide compounds release PH3 upon contact with water or acids, posing inhalation and fire hazards. Handle Ca3P2 under dry, inert conditions; avoid moisture and acids; store and dispose of according to applicable regulations.