Synthesis, Crystal Structure, and Bonding Analysis of the Hypoelectronic Cubic Phase Ca5Pd6Ge6

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• 作者：Isa Doverbratt ; Sim茅on Ponou ; Fei Wang ; Sven Lidin
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：September 21, 2015
• 年：2015
• 卷：54
• 期：18
• 页码：9098-9104
• 全文大小：495K
• ISSN：1520-510X

文摘

The title compound, Ca<sub>5sub>Pd<sub>6sub>Ge<sub>6sub>, was obtained during a systematic investigation of the Ca鈥揚d鈥揋e ternary phase diagram. The crystal structure was determined and refined from single-crystal X-ray diffraction data. It crystallizes in a new structure variant of the Y<sub>4sub>PdGa<sub>12sub>-type structure (Im3虆m, a = 8.7764(4) 脜) that features an arrangement of vertex-sharing body-centered cubes of calcium, Ca@Ca<sub>8sub>, with a hierarchical bcc network, interpenetrating a second (Pd<sub>6sub>Ge<sub>6sub>) network consisting of Ge<sub>2sub> dumbbells surrounded by Pd in a strongly flattened octahedron with Pd(渭<sup>2sup>-畏<sup>2sup>,畏<sup>4sup>-Ge<sub>2sub>)-like motifs. These octahedra are condensed through the Pd to form a 3D open fcc network. Theoretical band structure calculations suggested that the compound is hypoelectronic with predominantly multicenter-type interatomic interactions involving all three elements and essentially a Hume鈥揜othery-like regime of electronic stabilization. The similar electronegativity between germanium and palladium atoms has a decisive impact on the bonding picture of the system.