Remarkable Rare-Earth Metal Silicide Oxides with Planar Si6 Rings

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• 作者：Limin Wang ; Zhongjia Tang ; Bernd Lorenz ; Arnold M. Guloy
• 刊名：Journal of the American Chemical Society
• 出版年：2008
• 出版时间：August 27, 2008
• 年：2008
• 卷：130
• 期：34
• 页码：11258-11259
• 全文大小：159K
• 年卷期：v.130,no.34(August 27, 2008)
• ISSN：1520-5126

文摘

New rare-earth silicide oxides, La₁₀Si₈O₃ (1) and Ce₁₀Si₈O₃ (2), were synthesized through high-temperature reactions of the pure elements under controlled oxygen atmosphere conditions. The remarkable silicides crystallize in a unique crystal structure (space group P6/mmm; a = 10.975(3) Å (La) and 10.844(1) Å (Ce); c = 4.680(1) Å (La) and 4.561(1) Å (Ce)) that features a 3-D framework of corner-shared O-centered (La/Ce)₆ octahedra, reminiscent of hexagonal tungsten bronzes, with planar Si₆ rings enclosed within its hexagonal channels. Band structure calculations indicate the compounds are metallic, with optimized La−Si bonds, and a benzene-like [Si₆]⁶⁻ anion. Compound 1 exhibits temperature independent paramagnetism. Compound 2 exhibits Curie−Weiss paramagnetism, and an antiferromagnetic ordering below 7 K.