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Lithium nitride

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Lithium nitride
Identifiers
ChEBI
ECHA InfoCard 100.043.144 Edit this at Wikidata
EC Number
  • 247-475-2
  • InChI=1/3Li.N
Properties
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)
reacts
log P 3.24
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
reacts with water to release ammonia
Related compounds
Other anions
Lithium oxide
Other cations
Sodium nitride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Lithium 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 consist 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 forms a small amount of lithium nitride (along with lithium oxide, lithium hydroxide, and lithium carbonate) when it is exposed to air.

References

  • WebElements
  • Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
  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.: 1187–1188. doi:10.1039/a902962a.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  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.{{cite journal}}: CS1 maint: multiple names: authors list (link)