Europium(III) phosphide
Europium phosphide is an inorganic compound of europium and phosphorus with the chemical formula EuP. Other phosphides are also known.
Preparation
Heating powdered europium and red phosphorus in an inert atmosphere or vacuum:Passing phosphine through a solution of europium in liquid ammonia:
Eu2 is formed, which then decomposes to europium phosphide and phosphine:
Properties
Europium phosphide forms dark crystals which are stable in air and do not dissolve in water. Like sodium chloride, it crystallizes cubically in the space group Fm3''m with cell parameter a'' = 575.5 nm with four formula units per unit cell. Europium phosphide tends to form europium oxide in air, and pure EuP shows Van Vleck paramagnetism. The vapor pressure of EuP is 133-266.6 Pa at 1273 K.Europium phosphide actively reacts with nitric acid.