Strontium tungstate
| Names | |
|---|---|
| Other names
Strontium tungsten oxide | |
| Identifiers | |
| ECHA InfoCard | 100.033.275 |
| EC Number |
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PubChem CID |
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| Properties | |
| SrWO4 | |
| Molar mass | 335.46 g/mol |
| Appearance | White solid |
| Density | 6.439 g/cm3 (25 °C)[1] |
| Melting point | 1,535 °C (2,795 °F; 1,808 K) |
| Structure | |
| Tetragonal, scheelite type | |
| I41/a, No. 88 | |
| Hazards | |
| GHS labelling: | |
 | |
| Warning | |
| H315, H319, H335 | |
| P261, P305+P351+P338 | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Strontium tungstate is an inorganic compound with the chemical formula SrWO4. It is a white crystalline solid belonging to the scheelite family of tungstates.
Preparation
[edit]Strontium tungstate can be prepared by solid-state reaction of strontium carbonate with tungsten trioxide at high temperature:[1]
- SrCO3 + WO3 → SrWO4 + CO2↑
Polycrystalline material prepared by this route can be used as starting material for the growth of SrWO4 single crystals.[1]
Structure and properties
[edit]At ambient pressure, strontium tungstate crystallizes in the tetragonal crystal system with the scheelite structure, in space group I41/a (No. 88).[1][2]
The structure contains isolated WO42− tetrahedra surrounded by Sr2+ ions. SrWO4 has a density of about 6.44 g/cm3 and melts at approximately 1535 °C.[1]
Under pressure, SrWO4 undergoes structural phase transitions. A transition from the scheelite structure occurs near 10 GPa, producing a monoclinic high-pressure phase related to the fergusonite structure.[3]
Applications
[edit]Strontium tungstate is used and studied as an optical and luminescent material. SrWO4 single crystals have been investigated for Raman laser applications because of their strong Raman-active vibrational modes.
Rare-earth-doped SrWO4 materials are also used as phosphors. Doping with ions such as Sm3+ and Eu3+ can produce tunable yellow, orange and red emission for near-ultraviolet- and blue-excited light-emitting devices.[4]
References
[edit]- 1 2 3 4 5 Fan, Jiandong; Zhang, Huaijin; Wang, Zhengping; Ge, Wenwei; Wang, Jiyang (2006). "Synthesis of polycrystalline materials of SrWO4 and growth of its single crystal". Frontiers of Chemistry in China. 1: 264–. doi:10.1007/s11458-006-0023-z.
- ↑ Maurera, M. A. M. A.; Souza, A. G.; Soledade, L. E. B.; Pontes, F. M.; Longo, E.; Leite, E. R.; Varela, J. A. (2004). "Microstructural and optical characterization of CaWO4 and SrWO4 thin films prepared by a chemical solution method". Materials Letters. 58: 727–. doi:10.1016/j.matlet.2003.07.002.
- ↑ Errandonea, D.; Pellicer-Porres, J.; Manjón, F. J.; Segura, A.; Ferrer-Roca, Ch.; Kumar, R. S.; Tschauner, O. (2005). "High-pressure structural study of the scheelite tungstates CaWO4 and SrWO4". Physical Review B. 72 174106. doi:10.1103/PhysRevB.72.174106.
- ↑ Ren, Yandong; Liu, Yonghao; Yang, Rui (2016). "A series of color tunable yellow–orange–red-emitting SrWO4:RE (Sm3+, Eu3+–Sm3+) phosphor for near ultraviolet and blue light-based warm white light emitting diodes". Superlattices and Microstructures. 91: 138–. doi:10.1016/j.spmi.2015.12.026.