High-Pressure Synthesis and the Crystal Chemistry of Novel Transition Metal Compounds

本研究对新颖过渡金属化合物在高压和温度条件下的合成进行了研究。Various 3 d transition metal-metal- metalloid compounds were newly synthesized in this study。它们包括过渡金属二氟代化合物、数字化合物和三氟代化合物。这些金属化合物的晶体化学被系统地讨论在化学结合方案和压力诱导的阶段过渡的条款中。两种压力诱导的相位过渡类型，一种标记--到准氨酰胺--类型和一种标记--到CuAl-D22-类型，在过渡金属二氟代酮家族中找到。The former occurs in NiSbイD22エD2 and can be Oracle ained by effective packing of NiSbイD26エD2 octahedra。The latter在CrSb D22中发现了一个过渡性的变化，结合了字符形式混合的离子和共同金属。高压力形式的CrSb D22-D2展示了具有Curie温度的160 K.2的itinirant electron ferromagnetic行为。Various Group 14 elements could be inserted into the body-centered vacant site of the CoSb D23 y D2 skutterudite host lattice， resulting in the formation of the new filled-skutterudite。该耦合原子显示出较大的热振动振幅，并指示材料的热行为的可能减少。它被结合在一起，以便将原子插入到skutterudite主机晶格中，在开发新的热电转换材料中是有效的。

This research put emphasis on the synthesis of novel transition metal compounds under high pressure and temperature condition. Various 3d transition metal - metalloid compounds were newly synthesized in this study. These include transition metal diantimonides, digermanides, and triantimonides. The crystal chemistry of these intermetallic compounds was systematically discussed in terms of chemical bonding scheme and the pressure-induced phase transition.1. Two types of pressure-induced phase transitions, marcasite- to pararammelsbergite-type and marcasite- to CuAlィイD22ィエD2-type, were found in transition metal diantimonide family. The former occurs in NiSbィイD22ィエD2 and can be explained by effective packing of NiSbィイD26ィエD2 octahedra. The latter was found in CrSbィイD22ィエD2 and the transition accompanied a change in bonding character form mixed ionic and covalent to metallic. High-pressure form of CrSbィイD22ィエD2 showed an itinirant electron ferromagnetic behavior with the Curie temperature of 160 K.2. Various Group 14 elements could be inserted into the body-centered vacant site of the CoSbィイD23ィエD2 skutterudite host lattice, resulting in the formation of new filled-skutterudite. The incorporated atom showed large thermal vibration amplitude, indicating a possible reduction of thermal conductivity of materials. It was concluded that the atom insertion into the skutterudite host lattice is effective in developing new thermoelectric conversion materials.