Zinc nitride (Zn<sub>3</sub>N<sub>2</sub>) is an inorganic compound of zinc and nitrogen, usually obtained as (blue)grey crystals. It is a semiconductor. In pure form, it has the anti-bixbyite structure.
Zinc nitride can be obtained by thermally decomposing zincamide (zinc diamine) in an environment, at temperatures in excess of 200 ðC. The by-product of the reaction is ammonia. <blockquote>3 Zn(NH<sub>2</sub>)<sub>2</sub> â Zn<sub>3</sub>N<sub>2</sub> + 4 NH<sub>3</sub></blockquote>
It can also be formed by heating zinc to 600 ðC in a current of ammonia; the by-product is hydrogen gas. <blockquote>3 Zn + 2 NH<sub>3</sub> â Zn<sub>3</sub>N<sub>2</sub> + 3 H<sub>2</sub></blockquote> The decomposition of Zinc Nitride into the elements at the same temperature is a competing reaction. At 700 ðC Zinc Nitride decomposes. It has also been made by producing an electric discharge between zinc electrodes in a nitrogen atmosphere. Thin films have been produced by chemical vapour deposition of Bis(bis(trimethylsilyl)amido]zinc with ammonia gas onto silica or ZnO coated alumina at 275 to 410 ðC.
The crystal structure is anti-isomorphous with Manganese(III) oxide. (bixbyite). The heat of formation is c. per mol. It is a semiconductor with a reported bandgap of c. 3.2eV, however, a thin zinc nitride film prepared by electrolysis of molten salt mixture containing Li<sub>3</sub>N with a zinc electrode showed a band-gap of 1.01 eV.
Zinc nitride reacts violently with water to form ammonia and zinc oxide. <blockquote>Zn<sub>3</sub>N<sub>2</sub> + 3 H<sub>2</sub>O â 3 ZnO + 2 NH<sub>3</sub></blockquote>
Zinc nitride reacts with lithium (produced in an electrochemical cell) by insertion. The initial reaction is the irreversible conversion into LiZn in a matrix of beta-Li<sub>3</sub>N. These products then can be converted reversibly and electrochemically into LiZnN and metallic Zn.