Lithium nitride

Lithium nitride
Preferred IUPAC name

Lithium nitride
Other names

Trilithium nitride
Identifiers
CAS number 26134-62-3 Y
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, 1086 K, 1495 °F
Solubility in water reacts
log P 3.24
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
 N (verify) (what is: Y/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Lithium nitride (also trilithium nitride) is a compound of lithium and nitrogen 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.

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. Solid lithium nitride is a fast ion conductor and has the highest conductivity of any inorganic lithium salt. It has been studied extensively as a solid electrolyte and an anode material for use in batteries.[1] It can be formed by direct reaction of the elements, either by burning lithium metal in pure nitrogen gas or by reacting nitrogen gas with lithium dissolved in liquid sodium metal.[2] The second method gives a purer product. Lithium nitride reacts violently with water to produce ammonia:

Li3N (s) + 3 H2O (l) → 3 LiOH (aq) + NH3 (g)

Other alkali and alkaline earth nitrides also react in this manner, due to the high basicity of the nitride. 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 itself:

Li3N (s) + 2 H2 (g) → LiNH2 (s) + 2 LiH (s)

Lithium nitride is being investigated as a potential 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.[3]

Lithium nitride reacts with air to make lithium oxide, lithium hydroxide, and lithium carbonate.

References

  1. ^ US patent 4888258 (1989)
  2. ^ 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. 
  3. ^ Ping Chen, Zhitao Xiong, Jizhong Luo, Jianyi Lin and Kuang Lee Tan (2002). "Interaction of hydrogen with metal nitrides and imides". Nature 420 (6913): 302–304. doi:10.1038/nature01210. PMID 12447436.