Molybdenum Phosphide, MoP

Molybdenum Phosphide, MoP, is formed when molybdenum trioxide is fused with phosphoric acid and a little chalk, and the grey crystalline metallic mass is extracted first with hydrochloric acid and then with caustic soda. It has density 6.17, and is readily oxidised on heating in air, treating with nitric acid, or fusing with potassium nitrate.