High-Pressure Synthesis, Crystal Structure Determination, and a Ca Substitution Study of the Metallic Rhodium Oxide NaRh2O4

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• 作者：Kazunari Yamaura ; Qingzhen Huang ; Monica Moldovan ; David P. Young ; Akira Sato ; Yuji Baba ; Takuro Nagai ; Yoshio Matsui ; and Eiji Takayama-Muromachi
• 刊名：Chemistry of Materials
• 出版年：2005
• 出版时间：January 25, 2005
• 年：2005
• 卷：17
• 期：2
• 页码：359 - 365
• 全文大小：263K
• 年卷期：v.17,no.2(January 25, 2005)
• ISSN：1520-5002

文摘

The sodium rhodate NaRh₂O₄ was synthesized for the first time and characterized by neutron andX-ray diffraction studies and measurements of magnetic susceptibility, specific heat, electrical resistivity,and the Seebeck coefficient. NaRh₂O₄ crystallizes in the CaFe₂O₄-type structure, which is comprised ofa characteristic RhO₆ octahedral network. The compound is metallic in nature, probably reflecting the1:1 mixed valence character of Rh(III) and Rh(IV) in the network. For further studies of the compound,the Rh valence was varied significantly by means of an aliovalent substitution: the full-range solid solutionbetween NaRh₂O₄ and CaRh₂O₄ was achieved and characterized as well. The metallic state wasdramatically altered, and a peculiar magnetism developed in the low Na concentration range.