Zinc diphosphide

Zinc diphosphide (ZnP2) is an inorganic chemical compound. It is a red semiconductor solid with a band gap of 2.1 eV. It is one of the two compounds in the zinc-phosphorus system, the other being zinc phosphide (Zn3P2).

Synthesis and reactions
Zinc diphosphide can be prepared by the reaction of zinc with phosphorus.
 * 2 Zn +  P4   →  2 ZnP2

Structure
ZnP2 has a room-temperature tetragonal form that converts to a monoclinic form at around 990 °C. In both of these forms, there are chains of P atoms, helical in the tetragonal, semi-spiral in the monoclinic.

This compound is part of the Zn-Cd-P-As quaternary system and exhibit partial solid-solution with other binary compounds of the system.

Safety
ZnP2, like Zn3P2, is highly toxic due to the release of phosphine gas when the material reacts with gastric acid.