Lithium phosphide

Lithium phosphide

Names
Other names Trilithium phosphide
Identifiers
CAS Number	12057-29-3
3D model (JSmol)	Interactive image
ChemSpider	74796
ECHA InfoCard	100.031.824
EC Number	235-020-0
PubChem CID	25199615
CompTox Dashboard (EPA)	DTXSID4065232
InChI InChI=1S/3Li.H2P/h;;;1H2/q3*+1;-1 Key: IEAMEDSGNMSUND-UHFFFAOYSA-N
SMILES [Li+].[Li+].[Li+].[P-3]
Properties
Chemical formula	Li3P
Molar mass	51.79 g·mol−1
Appearance	Red-brown crystals
Density	1.43 g/cm3
Solubility in water	Reacts
Structure
Crystal structure	cubic
Related compounds
Other anions	Lithium nitride Lithium arsenide
Other cations	Sodium phosphide Calcium phosphide Aluminium phosphide Scandium phosphide Lanthanum phosphide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Lithium phosphide is an inorganic compound of lithium and phosphorus with the chemical formula Li₃P. This dark colored compound is formally the lithium salt of phosphine, consisting of lithium cations Li⁺ and phosphide anions P³⁻. It is hazardous to handle because of its high reactivity toward air.^[1]

Heating red phosphorus and lithium in an argon atmosphere:^[1]

12 Li + P₄ → 4 Li₃P

Reaction of monolithium phosphide and lithium:

LiP + 2 Li → Li₃P

Lithium phosphide forms red-brown crystals of hexagonal systems, space group P6₃/mmc,^[2] cell parameters a = 0.4264 nm, c = 0.7579 nm, Z = 2.^[3][4]

The compound reacts with water to release phosphine:^[5]

Li₃P + 3 H₂O → 3 LiOH + PH₃

The compound is proposed to be used as a potential electrolyte for solid-state devices.^[6]

Reaction of lithium with red phosphorus at 870 °C gives Li₃P₇.^[7]

• Nazri, Gholamabbas (1 April 1989). "Preparation, structure and ionic conductivity of lithium phosphide". Solid State Ionics. 34 (1–2): 97–102. doi:10.1016/0167-2738(89)90438-4.

Alkali metal phosphides are dangerous compounds when exposed to oxygen or moisture.^[8]