Chemistry:Zinc selenate
| Names | |
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| Other names
Zinc(II) selenate
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| Identifiers | |
PubChem CID
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| Properties | |
| ZnSeO4 | |
| Molar mass | 208.35 g/mol |
| Appearance | Crystalline solid |
| Soluble in water | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Zinc selenate is an inorganic compound of zinc and the selenate ion, with the chemical formula ZnSeO4. Several hydrated forms are known, including the monohydrate and hexahydrate.
Preparation
Zinc selenate can be prepared by reaction of zinc oxide with selenic acid:[1]
- ZnO + H2SeO4 → ZnSeO4 + H2O
Hydrated zinc selenate can also be obtained by precipitation or crystallization from aqueous zinc and selenate solutions. Crystallization from water commonly gives zinc selenate hexahydrate, ZnSeO4·6H2O.[2]
Properties
Hydrates and structure
Zinc selenate hexahydrate crystallizes in the tetragonal crystal system in the chiral space group P41212 or its enantiomorphic counterpart P43212.[3]
For one optically levorotatory crystal, the lattice parameters were a = 6.947(1) Å and c = 18.592(1) Å, with four formula units per unit cell and a calculated density of 2.342 g/cm3.[3]
The crystal is optically active because the hydrate adopts a chiral crystal structure. Its optical rotatory dispersion has been measured between approximately 366 and 633 nm.[3]
Other hydrates are also known. Zinc selenate monohydrate, ZnSeO4·H2O, can form at higher temperatures, while the hexahydrate is favored at lower temperatures.[4]
Thermal decomposition
Hydrated zinc selenate loses water on heating before the anhydrous selenate decomposes at higher temperature. Thermal-analysis studies of divalent-metal selenates found zinc selenate to be among the more thermally stable members of the series.[5]
Further heating ultimately gives zinc oxide as the zinc-containing residue.[5]
Applications
Zinc selenate has been used as a precursor for the preparation of zinc selenide. Reduction of hydrated zinc selenate under carbon monoxide can produce nanocrystalline ZnSe at temperatures around 460 °C.[2]
References
- ↑ Zhang, Qinglian, ed (in zh). 无机化学丛书 第六卷：卤素 铜分族 锌分族. Science Press. p. 735.
- ↑ 2.0 2.1 "Application and preparation of ZnSe nanometer powder by reduction process". Ceramics International 31 (4): 531–536. 2005. doi:10.1016/j.ceramint.2004.07.006.
- ↑ 3.0 3.1 3.2 Stadnicka, K.; Glazer, A. M.; Koralewski, M. (1988). "Structure and absolute optical chirality of zinc selenate hexahydrate". Acta Crystallographica Section B 44 (4): 356–361. doi:10.1107/S0108768188002253.
- ↑ Solubilities of Inorganic and Metal-Organic Compounds. Pergamon Press.
- ↑ 5.0 5.1 "Thermal decomposition of some divalent metal selenates". Thermochimica Acta 11 (2): 187–196. 1975. doi:10.1016/0040-6031(75)80022-0.
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