Lithium phosphide
Other names
Trilithium phosphide
3D model (JSmol)
ECHA InfoCard 100.031.824 Edit this at Wikidata
EC Number
  • 235-020-0
  • InChI=1S/3Li.H2P/h;;;1H2/q3*+1;-1
  • [Li+].[Li+].[Li+].[PH2-]
Molar mass 51.79 g·mol−1
Appearance Red-brown crystals
Density 1.43
Related compounds
Other cations
Scandium phosphide
Lanthanum phosphide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Lithium phosphide is an inorganic compound of lithium and phosphorus with the chemical formula Li
. This dark colored compound is formally the Li+ salt of P3-. It is a hazardous to handle because of its high reactivity toward air.[1]


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

12Li + P4 → 4Li3P

Reaction of monolithium phosphide and lithium:

LiP + 2Li → Li3P

Physical and chemical properties

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 react with water to release phosphine:[5]

Li3P + 3H2O → 3LiOH + PH3


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

Related compounds

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

Further reading


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


  1. ^ a b E. Donges (1963). "Phosphides, Arsenides, Antimonides and Bismuthides of Alkali Metals from the Elements". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 2. NY, NY: Academic Press. p. 985.
  2. ^ "mp-736: Li3P (hexagonal, P6_3/mmc, 194)". Retrieved 10 December 2021.
  3. ^ Seel, Max; Pandey, Ravi (1990). "Band Structure and Electronic Properties of Lithium Phosphide Li3P". MRS Proceedings. 210. doi:10.1557/PROC-210-155. Retrieved 10 December 2021.
  4. ^ Donnay, Joseph Désiré Hubert (1963). Crystal Data; Determinative Tables. American Crystallographic Association. p. 765. Retrieved 10 December 2021.
  5. ^ Dong, Yongkwan; DiSalvo, Francis J. (15 April 2007). "Reinvestigation of trilithium phosphide, Li 3 P". Acta Crystallographica Section E. 63 (4): i97–i98. doi:10.1107/S1600536807008422.
  6. ^ Wan, Chaoying; Huang, Xingyi; Bowen, Chris (23 June 2021). Two-dimensional Inorganic Nanomaterials for Conductive Polymer Nanocomposites. Royal Society of Chemistry. ISBN 978-1-83916-260-2. Retrieved 10 December 2021.
  7. ^ Manriquez, V.; Hönle, W.; von Schnering, H. G. (1986). "Zur Chemie und Strukturchemie von Phosphiden und Polyphosphiden. 42. Trilithiumheptaphosphid Li3P7: Darstellung, Struktur und Eigenschaften". Zeitschrift für Anorganische und Allgemeine Chemie. 539 (8): 95–109. doi:10.1002/zaac.19865390810.
  8. ^ Toxic Substances Control Act (TSCA) Chemical Substance Inventory. U.S. Government Printing Office. 1979. p. 9. Retrieved 10 December 2021.