HIGH-PRESSURE SYNTHESIS AND CRYSTAL-STRUCTURE OF A NEW SERIES OF PEROVSKITE-LIKE COMPOUNDS CMN7O12(C = NA, CA, CD, SR, LA, ND)
HIGH-PRESSURE SYNTHESIS AND CRYSTAL-STRUCTURE OF A NEW SERIES OF PEROVSKITE-LIKE COMPOUNDS CMN7O12(C = NA, CA, CD, SR, LA, ND)
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DOI：
10.1016/0022-4596(74)90102-9
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发表时间：
1974-01-01
影响因子：
3.3
通讯作者：
MAREZIO, M
中科院分区：
文献类型：
--
作者：
BOCHU, B;CHENAVAS, J;MAREZIO, M
在高压高温条件下合成了一系列新的类钙钛矿化合物cmn7o12。C是一个大的二价或三价阳离子，如Ca， Cd, Sr， La和Nd。用粉末x射线数据测定了淬火材料的组织。它们是纳米7 O 12立方结构的变形。[c2 + mn3 + 3](mn3 + 3mn4 +) o12化合物是三角形的（r3）。钙钛矿结构的C 2+、Mn 3+以及Mn 3+、Mn 4+阳离子分别排列在相应的A位和B位上。[c3 + mn3 + 3](mn3 + 4) o12化合物是单斜的（I 2 m）。在这些化合物中，顺序只存在于A位。结果表明，较低的对称性可能是由于占据B位的mn3 +阳离子的协同Jahn-Teller效应的结果。
A new series of perovskite-like compounds CMn 7 O 12 have been synthesized under high pressure and high temperature conditions. C is a large divalent or trivalent cation such as Ca, Cd, Sr, La and Nd. The structures of the quenched materials have been determined from powder X-ray data. They are distortions of the NaMn 7 O 12 cubic structure. The [C 2+ Mn 3+ 3](Mn 3+ 3 Mn 4+) O 12 compounds are trigonal (R 3). The C 2+ and Mn 3+ as well as the Mn 3+ and Mn 4+ cations are ordered on the corresponding A and B sites of the perovskite structure, respectively. The [C 3+ Mn 3+ 3](Mn 3+ 4) O 12 compounds are monoclinic (I 2 m). In these compounds the order exists only in the A sites. It is shown that the lower symmetry may be the result of a cooperative Jahn-Teller effect of the Mn 3+ cations occupying the B sites.