// Workers AI · dad joke modeWhat did magnesium tungstate say? "I'm a compound interest.
| Names | |
|---|---|
| Other names
Magnesium tungsten oxide | |
| Identifiers | |
| ECHA InfoCard | 100.033.621 |
| EC Number |
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PubChem CID |
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CompTox Dashboard (EPA) |
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| Properties | |
| MgWO4 | |
| Molar mass | 272.14 g/mol |
| Appearance | White solid |
| Melting point | 1,358 °C (2,476 °F; 1,631 K) |
| Practically insoluble in water | |
| Structure | |
| Monoclinic, wolframite type | |
| P2/c, No. 13 | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Magnesium tungstate is an inorganic compound with the chemical formula MgWO4. It is a white, water-insoluble solid that crystallizes in the wolframite structure. It occurs naturally as the rare mineral huanzalaite.
Occurrence
[edit]Magnesium tungstate occurs naturally as huanzalaite, MgWO4, a rare member of the wolframite group.
Preparation
[edit]Magnesium tungstate can be prepared by solid-state reaction of magnesium oxide with tungsten trioxide:
- MgO + WO3 → MgWO4
It can also be precipitated from aqueous solutions of a magnesium salt and sodium tungstate. For example:
- Mg(NO3)2 + Na2WO4 → MgWO4↓ + 2 NaNO3
Structure and properties
[edit]Magnesium tungstate crystallizes in the monoclinic crystal system with the wolframite-type structure, in space group P2/c (No. 13). The structure consists of distorted MgO6 and WO6 octahedra arranged in chains.
A high-temperature polymorph is reported above about 1065 °C.[1]
Hydrated forms are also known. The dihydrate, MgWO4·2H2O, crystallizes in space group P21/c and dehydrates topotactically on heating to give anhydrous MgWO4.[2]
A monohydrate, MgWO4·H2O, has also been prepared and structurally characterized.[3]
At high pressure, MgWO4 undergoes structural changes similar to those observed in related wolframite-type tungstates.[4]
Applications
[edit]Magnesium tungstate is a luminescent material and has been used and investigated as a phosphor. Its emission is associated primarily with electronic transitions involving the tungstate groups.
MgWO4 has also been investigated as a scintillating material and as a host lattice for luminescent dopants.
References
[edit]- ↑ Ropp, Richard C. (2012). Encyclopedia of the Alkaline Earth Compounds. Newnes. p. 845. ISBN 978-0-444-59553-9.
- ↑ Günter, John R.; Dubler, Erich (1986). "Crystal structure and topotactic dehydration of magnesium tungstate dihydrate, MgWO4·2H2O". Journal of Solid State Chemistry. 65: 118–. doi:10.1016/0022-4596(86)90096-4.
- ↑ Amberg, M.; Günter, J. R.; Schmalle, H.; Blasse, G. (1988). "Preparation, crystal structure, and luminescence of magnesium molybdate and tungstate monohydrates, MgMoO4·H2O and MgWO4·H2O". Journal of Solid State Chemistry. 77: 162–. doi:10.1016/0022-4596(88)90104-1.
- ↑ Ruiz-Fuertes, J.; Errandonea, D.; López-Moreno, S.; González, J.; Gomis, O.; Vilaplana, R.; Manjón, F. J. (2011). "High-pressure Raman spectroscopy and lattice-dynamics calculations on scintillating MgWO4: Comparison with isomorphic compounds". Physical Review B. 83 214112. doi:10.1103/PhysRevB.83.214112.