Basic Zinc Nitrates

The following have been described: -

1. By evaporating zinc nitrate solutions or heating hydrated zinc nitrate (sometimes followed by treatment with water), Zn(NO₃)₂.7ZnO.2H₂O; 3Zn(NO₃)₂.ZnO.3H₂O; 4Zn(NO₃)₂.3ZnO.14H₂O; Zn(NO₃)₂.3ZnO.3H₂O; 2Zn(NO₃)₂.7ZnO.Aq.; Zn(NO₃)₂.2ZnO.
2. By treating nitric acid with excess of zinc, Zn(NO₃)₂.5ZnO.8H₂O; Zn(NO₃)₂.4ZnO.5H₂O; Zn(NO₃)₂.3ZnO.4H₂O.
3. By precipitating excess of zinc nitrate solution with ammonia, Zn(NO₃)₂.7ZnO.4H₂O.
4. By heating hydrated or basic zinc nitrates with water in sealed tubes, Zn(NO₃)₂.5ZnO.7H₂O; Zn(NO₃)₂.4ZnO.6H₂O; HNO₃.2ZnO.H₂O.
5. By heating zinc nitrate solution with zinc oxide, Zn(NO₃)₂.ZnO.3H₂O.

Andre obtained the hydrated tetrammoniate, 3[Zn(NO₃)₂.4NH₄]+2H₂O, from the solution prepared by passing an excess of ammonia gas into zinc nitrate solution. The deliquescent crystals are very soluble in a little water, and readily decomposed by excess with the precipitation of zinc oxide. The warm aqueous solution also dissolves zinc oxide, and 3Zn(NO₃)₂.10ZnO.4NH₄.18H₂O, stable in air, insoluble in cold water and decomposed by hot, deposits from the filtered solution.

Anhydrous Zn(NO₃)₂.4NH₄ is obtained by leading ammonia gas in excess through a saturated solution of zinc nitrate, adding alcohol, drying the precipitate, and finally warming it at 100° C. in a stream of ammonia.

It absorbs a quantity of ammonia gas at room temperature that closely corresponds to the formation of the hexammoniate, and only a little more ammonia is absorbed on cooling to - 18° C. As the temperature is raised, evolution of gas commences distinctly at 30.5° C., and as the temperature rises further the tetrammoniate is formed, which decomposes at 206° C.

The double salt, 3Zn(NO₃)₂.2Bi(NO₃)₃.24H₂O, has been described.