[citation needed] It may be formed by reaction of the elements,[1] but it is more commonly prepared by carbothermal reduction of calcium phosphate:[2] This is also the way how it was accidentally discovered by Smithson Tennant in 1791 while verifying the composition of carbon dioxide proposed by Antoine Lavoisier by reducing calcium carbonate with phosphorus.

The acid in the digestive system of the rodent reacts with the phosphide to generate the toxic gas phosphine.

This method of vermin control has possible use in places where rodents immune to many of the common warfarin-type (anticoagulant) poisons have appeared.

Calcium phosphide is also used in fireworks, torpedoes, self-igniting naval pyrotechnic flares, and various water-activated ammunition.

It is speculated that calcium phosphide—made by boiling bones in urine, within a closed vessel—was an ingredient of some ancient Greek fire formulas.