High-Pressure Synthesis, Crystal Structure, and Unusual Valence State of Novel Perovskite Oxide CaCu3Rh4O12

详细信息    查看全文

• 作者：Ikuya Yamada ; Mikiko Ochi ; Masaichiro Mizumaki ; Atsushi Hariki ; Takayuki Uozumi ; Ryoji Takahashi ; Tetsuo Irifune
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：July 21, 2014
• 年：2014
• 卷：53
• 期：14
• 页码：7089-7091
• 全文大小：220K
• ISSN：1520-510X

文摘

A novel perovskite oxide, CaCu₃Rh₄O₁₂, has been synthesized under high-pressure and high-temperature conditions (15 GPa and 1273 K). Rietveld refinement of synchrotron X-ray powder diffraction data indicates that this compound crystallizes in a cubic AA鈥?sub>3B₄O₁₂-type perovskite structure. Synchrotron X-ray absorption and photoemission spectroscopy measurements reveal that the Cu and Rh valences are nearly trivalent. The spectroscopic analysis based on calculations suggests that the appropriate ionic model of this compound is Ca²⁺Cu^2.8+₃Rh^3.4+₄O₁₂, as opposed to the conventional Ca²⁺Cu²⁺₃Rh⁴⁺₄O₁₂. The uncommon valence state of this compound is attributed to the relative energy levels of the Cu 3d and Rh 4d orbitals, in which the large crystal-field splitting energy of the Rh 4d orbitals is substantial.