Zinc diphosphide

Zinc diphosphide (ZnP₂) is an inorganic chemical compound. It is a red semiconductor solid with a band gap of 2.1 eV.^[2] It is one of the two compounds in the zinc-phosphorus system, the other being zinc phosphide (Zn₃P₂).

Zinc diphosphide

Identifiers
CAS Number	12037-79-5
3D model (JSmol)	Interactive image
ChemSpider	141421
EC Number	234-867-3
InChI InChI=1S/P2.Zn/c1-2;/q-2;+2 Key: WHCVAYNMVBDLCU-UHFFFAOYSA-N
SMILES [P-]=[P-].[Zn+2]
Properties
Chemical formula	ZnP2
Molar mass	127.33 g/mol
Appearance	red crystals
Density	3.53 g/cm3
Melting point	1,040 °C (1,900 °F; 1,310 K)
Structure
Crystal structure	Tetragonal, tP24
Space group	P41212, No. 92[1]
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

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.^[3] In both of these forms, there are chains of P atoms, helical in the tetragonal, semi-spiral in the monoclinic.^[4]

This compound is part of the Zn-Cd-P-As quaternary system and exhibit partial solid-solution with other binary compounds of the system.^[5]

Safety

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