Cobalt arsenide

Cobalt arsenide is a binary inorganic compound of cobalt and arsenic with the chemical formula CoAs. The compound occurs naturally as the mineral modderite.

Physical properties
Cobalt arsenide crystallizes in the orthorhombic system, space group Pnam, parameter parameters a = 0.515 nm, b = 0.596 nm, c = 0.351 nm, Z = 4.

Cobalt arsenide is isostructural with FeAs.

At approximately 6-8 GPa, single crystals of CoAs undergo a transformation to a lower-symmetry phase.

Use
CoAs is used as a semiconductor and in photo optic applications.