Strontium tungstate

Strontium tungstate
Names
	Other names Strontium tungsten oxide
Identifiers
CAS Number	13451-05-3 ;
ECHA InfoCard	100.033.275
EC Number	236-617-9;
PubChem CID	123306;
Properties
Chemical formula	SrWO4
Molar mass	335.46 g/mol
Appearance	White solid
Density	6.439 g/cm3 (25 °C)
Melting point	1,535 °C (2,795 °F; 1,808 K)
Structure
Crystal structure	Tetragonal, scheelite type
Space group	I41/a, No. 88
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335
Precautionary statements	P261, P305+P351+P338
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Strontium tungstate is an inorganic compound with the chemical formula SrWO₄. It is a white crystalline solid belonging to the scheelite family of tungstates.

Structure and properties

At ambient pressure, strontium tungstate crystallizes in the tetragonal crystal system with the scheelite structure, in space group I4₁/a (No. 88).

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.

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.

Preparation

Strontium tungstate can be prepared by solid-state reaction of strontium carbonate with tungsten trioxide at high temperature:

SrCO₃ + WO₃ → SrWO₄ + CO₂↑

Polycrystalline material prepared by this route can be used as starting material for the growth of SrWO₄ single crystals.

Applications

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.

References

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. arXiv:cond-mat/0504133. 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.

[Fan-1] 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.

[2] 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.

[HP-3] 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. arXiv:cond-mat/0504133. doi:10.1103/PhysRevB.72.174106.

[4] 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.