Lithium nitride

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Lithium nitride
Unit cell ball and stick model of lithium nitride
Identifiers
CAS number 26134-62-3 YesY
EC number 247-475-2
ChEBI CHEBI:30525 N
Jmol-3D images Image 1
Properties
Molecular formula Li3N
Molar mass 34.83 g/mol
Appearance red, purple solid
Density 1.270 g/cm3
Melting point 813 °C (1,495 °F; 1,086 K)
Solubility in water reacts
log P 3.24
Structure
Crystal structure see text
Hazards
EU Index Not listed
Main hazards reacts with water to release ammonia
Related compounds
Other anions Lithium oxide
Other cations Sodium nitride
Related compounds Lithium amide Lithium imide
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N (verify) (what is: YesY/N?)
Infobox references

Lithium nitride is a compound with the formula Li3N. It is the only stable alkali metal nitride. The solid is a red or purple color and has a high melting point.[1]

Preparation and handling[edit]

Lithium nitride is prepared by direct combination of elemental lithium with nitrogen gas:[2]

6 Li + N2 → 2 Li3N

Instead of burning lithium metal in an atmosphere of nitrogen, a solution of lithium in liquid sodium metal can be treated with N2. Lithium nitride reacts violently with water to produce ammonia:

Li3N + 3 H2O → 3 LiOH + NH3

Structure[edit]

Li3N has an unusual crystal structure that consists of two types of layers, one sheet has the composition Li2N contains 6-coordinate Li centers and the other sheet consists only of lithium cations.[3]

The hypothetical nitride ion, N3−, would be an extremely strong Brønsted base, easily qualifying as a superbase. It is, in fact, a stronger base than the hydride ion, and so deprotonates hydrogen:

Li3N + 2 H2 → LiNH2 + 2 LiH

Lithium nitride has been investigated as a storage medium for hydrogen gas, as the reaction is reversible at 270 °C. Up to 11.5% by weight absorption of hydrogen has been achieved.[4]

References[edit]

  1. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 0080379419. 
  2. ^ E. Döneges "Lithium Nitride" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 984.
  3. ^ Barker M.G., Blake A.J, Edwards P.P., Gregory D.H., Hamor T. A., Siddons D. J., Smith S. E. (1999). "Novel layered lithium nitridonickelates; effect of Li vacancy concentration on N co-ordination geometry and Ni oxidation state". Chem. Commun. (13): 1187–1188. doi:10.1039/a902962a. 
  4. ^ Ping Chen, Zhitao Xiong, Jizhong Luo, Jianyi Lin and Kuang Lee Tan (2002). "Interaction of hydrogen with metal nitrides and amides". Nature 420 (6913): 302–304. doi:10.1038/nature01210. PMID 12447436. 

See also[edit]