Crystal Growth, Structures, and Properties of the Complex Borides, LaOs2Al2B and La2Os2AlB2

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• 作者：Daniel E. Bugaris ; Fei Han ; Jino Im ; Duck Young Chung ; Arthur J. Freeman ; Mercouri G. Kanatzidis
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：August 17, 2015
• 年：2015
• 卷：54
• 期：16
• 页码：8049-8057
• 全文大小：581K
• ISSN：1520-510X

文摘

Single crystals of two novel quaternary metal borides, LaOs₂Al₂B and La₂Os₂AlB₂, have been grown from La/Ni eutectic fluxes. LaOs₂Al₂B crystallizes in tetragonal space group P4/mmm with the CeCr₂Si₂C-type structure, and lattice parameters a = 4.2075(6) 脜 and c = 5.634(1) 脜. La₂Os₂AlB₂ exhibits a new crystal structure in monoclinic space group C2/c with lattice parameters a = 16.629(3) 脜, b = 6.048(1) 脜, c = 10.393(2) 脜, and 尾 = 113.96(3)掳. Both structures are three-dimensional frameworks with unusual coordination (for solid-state compounds) of the boron atoms by transition metal atoms. The boron atom is square planar in LaOs₂Al₂B, whereas it exhibits linear and T-shaped geometries in La₂Os₂AlB₂. Electrical resistivity measurements reveal poor metal behavior (蟻_300聽K 鈭?900 渭惟 cm) for La₂Os₂AlB₂, consistent with the electronic band structure calculations, which also predict a metallic character for LaOs₂Al₂B.