Nickel tungstate
Chemical compound
From Wikipedia, the free encyclopedia
Nickel tungstate is an inorganic compound of nickel, tungsten and oxygen, with the chemical formula of NiWO4.
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| Names | |
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| Other names
Nickel(II) tungstate Nickel tungsten oxide | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.034.560 |
| EC Number |
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PubChem CID |
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CompTox Dashboard (EPA) |
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| Properties | |
| NiWO4 | |
| Molar mass | 306.534 |
| Appearance | green crystals[1] |
| Odor | odourless[1][2] |
| Density | 3.3723 g/cm³[3] |
| Melting point | 1420 ˚C[4] |
| insoluble[2] | |
| Solubility | soluble in ammonia |
| Structure | |
| monoclinic crystal system | |
| Hazards | |
| GHS labelling: | |
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| Danger | |
| H317, H350i, H372 | |
| P201, P260, P280, P308+P313, P405, P501 | |
| Related compounds | |
Other anions |
Nickel(II) chromate Nickel(II) molybdate |
Other cations |
Iron(II) tungstate Cobalt(II) tungstate Zinc(II) tungstate |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Preparation
Nickel tungstate can be prepared by the reaction of nickel(II) nitrate and sodium tungstate:[5]
- Ni(NO3)2 + Na2WO4 → NiWO4 + 2 NaNO3
Nickel tungstate can also be prepared by the reaction of nickel(II) oxide and tungsten(VI) oxide.[6]
It can also be obtained by the reaction of ammonium metatungstate and nickel(II) nitrate[7] or from the reaction of sodium tungstate, nickel(II) chloride and sodium chloride.[8]
Nickel tungstate undergoes a phase transition at 700 °C.[5]
Properties
Nickel tungstate is a light brown, odourless solid that is insoluble in water.[2] The amorphous form is green and the polycrystalline form is brown.[5] It crystallizes in the wolframite crystal structure of the monoclinic crystal system with space group P2/c (No. 13).[9][8] The compound is antiferromagnetic.[10][11]
Applications
Nickel tungstate has no commercial uses. It has been examined as a photocatalyst, in humidity sensors, and in dielectric resonators. It is also considered as a "promising" cathode material for asymmetric supercapacitors.[1][12]