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 dp>0p> transition metal tellurite, Na₆Te₄W₆O₂₉, was synthesized by solid-state methods. The material crystallizes in monoclinic space group P2₁/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 Na₆Te₄W₆O₂₉ (13 mm × 11 mm × 10 mm) and Na₂TeW₂O₉ (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: Δn₃ = n_z – n_x = 0.0828–0.1248 from 1062.6 to 450.2 nm for Na₆Te₄W₆O₂₉, and Δn₃ = n_z – n_x = 0.1471–0.2069 from 1062.6 to 450.2 nm for Na₂TeW₂O₉. The results indicate that Na₆Te₄W₆O₂₉ and Na₂TeW₂O₉ may have uses in applications involving birefrigent materials.