Large Birefringent Materials, Na6Te4W6O29 and Na2TeW2O9: Synthesis, Structure, Crystal Growth, and Characterization
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- 作者：Hongwei Yu ; Weiguo Zhang ; P. Shiv Halasyamani
- 刊名：Crystal Growth & Design
- 出版年：2016
- 出版时间：February 3, 2016
- 年：2016
- 卷：16
- 期：2
- 页码：1081-1087
- 全文大小：454K
- ISSN：1528-7505
文摘
A new d<sup>0sup> transition metal tellurite, Na<sub>6sub>Te<sub>4sub>W<sub>6sub>O<sub>29sub>, was synthesized by solid-state methods. The material crystallizes in monoclinic space group P2<sub>1sub>/c (No. 14) with the following values: a = 7.3297(3) ?, b = 21.9057(9) ?, c = 10.2871(3) ?, β = 133.490(2)°, and Z = 2. Additionally, large crystals of Na<sub>6sub>Te<sub>4sub>W<sub>6sub>O<sub>29sub> (13 mm × 11 mm × 10 mm) and Na<sub>2sub>TeW<sub>2sub>O<sub>9sub> (23 mm × 5 mm × 3 mm) were grown by the top seeded solution growth method. In addition to the crystal growth, refractive indices were measured, and the Sellmeier equations were fitted by using the minimum deviation technique. Interestingly, the two reported compounds exhibit relatively large birefringences: Δn<sub>3sub> = n<sub>zsub> – n<sub>xsub> = 0.0828–0.1248 from 1062.6 to 450.2 nm for Na<sub>6sub>Te<sub>4sub>W<sub>6sub>O<sub>29sub>, and Δn<sub>3sub> = n<sub>zsub> – n<sub>xsub> = 0.1471–0.2069 from 1062.6 to 450.2 nm for Na<sub>2sub>TeW<sub>2sub>O<sub>9sub>. The results indicate that Na<sub>6sub>Te<sub>4sub>W<sub>6sub>O<sub>29sub> and Na<sub>2sub>TeW<sub>2sub>O<sub>9sub> may have uses in applications involving birefrigent materials.