Calcium nitride explained

Calcium nitride is the inorganic compound with the chemical formula Ca₃N₂.^[1] It exists in various forms (isomorphs), α-calcium nitride being more commonly encountered.

Structure

α-Calcium nitride adopts an anti-bixbyite structure, similar to Mn₂O₃, except that the positions of the ions are reversed: calcium (Ca²⁺) take the oxide (O²⁻) positions and nitride ions (N³⁻) the manganese (Mn³⁺). In this structure, Ca²⁺ occupies tetrahedral sites, and the nitride centres occupy two different types of octahedral sites.^[2]

Synthesis and reactions

Calcium nitride is formed along with the oxide, CaO, when calcium burns in air. It can be produced by direct reaction of the elements:^[3]

3 Ca + N₂ → Ca₃N₂

It reacts with water or even the moisture in air to give ammonia and calcium hydroxide:^[4]

Ca₃N₂ + 6 H₂O → 3 Ca(OH)₂ + 2 NH₃Like sodium oxide, calcium nitride absorbs hydrogen above 350 °C:

Ca₃N₂ + 2 H₂ → 2 CaNH + CaH₂

External links

• WebElements entry

Notes and References

1. Book: Concise Encyclopedia Chemistry . Eagleson, M. . 1994 . Walter de Gruyter . 160 . registration . Calcium nitride. . 3-11-011451-8 .
2. Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. .
3. P. Ehrlich “Calcium, Strontium, Barium Nitrides Ca₃N₂, Sr₃N₂, Ba₃N₂” in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 940-1.
4. The Vibrational Spectra and Decomposition of α-Calcium Nitride (α-Ca₃N₂) and Magnesium Nitride (Mg₃N₂) . 1998 . Heyns, A. . Journal of Solid State Chemistry . 137 . 1 . 33–41 . 10.1006/jssc.1997.7672 . 1998JSSCh.137...33H .