Ternary Compounds in the Sn-Rich Section of the Ba–Ga–Sn System: Ba8Ga16–xSn30+x (1.1 ≤ x ≤ 2.8) Clathrates of Type-I and Type-VIII, and BaGa2–xSn4+x (x ≈ 0.2) with a Clathrate-like Structure

Crystals

关键词: clathrate type-I;    clathrate type-VIII;    barium;    gallium;    tin;    crystal structure;   

DOI  :  10.3390/cryst1030145

来源: DOAJ

【 摘 要 】

Systematic syntheses in the Ba–Ga–Sn system confirmed the existence of a new ternary phase BaGa1.79Sn4.21(2) (EuGa2Ge4 structure type; orthorhombic space group Cmcm, Pearson symbol oS28) with lattice parameters a = 4.5383(6) Å, b = 12.2486(16) Å, c = 14.3747(19) Å. The structure is best viewed as an open-framework based on tetrahedrally coordinated Sn/Ga atoms with Ba atoms enclosed in the voids within it. The new phase co-precipitates with two other compounds with very similar compositions—Ba8Ga14.5Sn31.5(4) (K4Si23 structure type; cubic space group , Pearson symbol cP54; a = 11.6800(12) Å), and Ba8Ga13.2Sn32.8(3), (Eu4Ga8Ge15 structure type; cubic space group , Pearson symbol cI54; a = 11.5843(7) Å). Detailed discussion on how syntheses affect the crystal chemistry, and the temperature dependence of the atomic displacement parameters, obtained from single-crystal structure refinements, are also reported in this article.

【 授权许可】

Unknown