American Chemical Society
ic401855j_si_001.cif (32.26 kB)

A‑Site-Ordered Perovskite MnCu3V4O12 with a 12-Coordinated Manganese(II)

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posted on 2016-02-18, 17:47 authored by Yasuhide Akizuki, Ikuya Yamada, Koji Fujita, Norimasa Nishiyama, Tetuo Irifune, Takeshi Yajima, Hiroshi Kageyama, Katsuhisa Tanaka
A novel cubic perovskite MnCu3V4O12 has been synthesized at a high pressure and high temperature of 12 GPa and 1373 K. This compound crystallizes in the A-site-ordered perovskite structure (space group Im3̅) with lattice constant a = 7.26684(10) Å at room temperature. The most notable feature of this compound lies in the fact that the Mn2+ ion is surrounded by 12 equidistant oxide ions to form a regular icosahedron; the situation of Mn2+ is unprecedented for the crystal chemistry of an oxide. An anomalously large atomic displacement parameter Uiso= 0.0222(8) Å2 is found for Mn2+ at room temperature, indicating that the thermal oscillation of the small Mn2+ ion in a large icosahedron is fairly active. Magnetic susceptibility and electric resistivity measurements reveal that 3d electrons of Mn2+ ions are mainly localized, while 3d electrons in Cu2+ and V4+ ions are delocalized and contribute to the metallic conduction.