物理化学学报 >> 2010, Vol. 26 >> Issue (07): 1823-1831.doi: 10.3866/PKU.WHXB20100726

结构化学 上一篇    下一篇

半水榴石型化合物Sr6Sb4M3O14(OH)10(M=Co, Mn)的合成、结构与性质

李阔, 王颖霞, 苏婕, 林建华   

  1. 北京大学化学与分子工程学院, 稀土材料化学与应用国家重点实验室, 北京分子科学国家实验室, 北京 100871
  • 收稿日期:2010-03-25 修回日期:2010-04-19 发布日期:2010-07-02
  • 通讯作者: 王颖霞, 林建华 E-mail:wangyx@pku.edu.cn; jhlin@pku.edu.cn

Syntheses, Structures and Properties of Hemi-Hydrogarnet Sr6Sb4M3O14(OH)10 (M=Co,Mn)

LI Kuo, WANG Ying-Xia, SU Jie, LIN Jian-Hua   

  1. Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
  • Received:2010-03-25 Revised:2010-04-19 Published:2010-07-02
  • Contact: WANG Ying-Xia, LIN Jian-Hua E-mail:wangyx@pku.edu.cn; jhlin@pku.edu.cn

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摘要：

在强碱性水热条件下合成了两种新化合物Sr6Sb4Co3O14 (OH)10 (SSC)与Sr6Sb4Mn3O14 (OH)10 (SSM). 采用粉末X射线衍射数据, 通过Rietveld方法进行了结构分析, 讨论了金属离子的拓扑结构. 两种化合物均为石榴石-水榴石相关结构, 空间群I-43d, 晶胞参数a分别为1.30634(2) nm (SSC)和1.31367(1) nm (SSM). 结构中, SbO6八面体与MO4(M=Co, Mn)四面体共顶点连接, Sb5+-M2+(M=Co, Mn)离子表现为ctn即C3N4型的拓扑结构. 拓扑结构中, Sb5+为三连接, 过渡金属离子M2+(M=Co, Mn)为四连接. Sb5+离子的拓扑结构为体心立方, 而M2+(M=Co, Mn)分布呈类风扇状, 相互连接形成thp型拓扑结构(即Th3P4中Th原子之间连接关系). 过渡金属离子的分布与化合物表现出的磁性质密切相关, Co2+(Mn2+)间存在反铁磁相互作用. Sr6Sb4Co3O14(OH)10在低温下表现出反铁磁倾斜有序. Sr6Sb4Co3O14(OH)10 和Sr6Sb4Mn3O14(OH)10在高温下发生分解, 产物主相为双钙钛矿Sr2(Sb, M)2O6(M=Co, Mn).

关键词: 拓扑结构, 半水榴石, 羟基氧化物, Rietveld结构精修, 反铁磁性倾斜

Abstract:

Two new compounds, Sr6Sb4Co3O14(OH)10 (SSC) and Sr6Sb4Mn3O14(OH)10 (SSM), were synthesized under hydrothermal conditions in an alkaline medium. Their structures were determined by powder X-ray diffraction using Rietveld analysis, and the topology of the metal cation network was discussed. These two isostructural compounds crystallize in a garnet-related or hydrogarnet-related structure with the space group I43d and the lattice parameters (a) are 1.30634(2) nm(SSC) and 1.31367(1) nm(SSM). The SbO6 octahedron and MO4 (M=Co, Mn) tetrahedron share corners with each other to formthe backbone of the structure. The topology of the Sb5+ andM2+ (M=Co,Mn) network is ctn, which is the C3N4network. The Sb5+ node is three-connected and that of M2+ (M=Co, Mn) is four-connected. The distribution of the M2+ (M=Co, Mn) cations in the structure is in a fanlike mode with a thp topology, i.e., a network of Th atoms in Th3P4. These two compounds are antiferromagnetic. Sr6Sb4Co3O14(OH)10 exhibits a net magnetic moment, which may be related to the canting ordering of Co2+ ions below 10 K. Sr6Sb4Co3O14(OH)10 and Sr6Sb4Mn3O14(OH)10 decompose above 300 ℃ and give rise to the perovskite-type compounds Sr2(Sb, M)2O6(M=Co, Mn) as the main phases in the products after treatment at 900 ℃ under atmospheric conditions.

Key words: Topological structure, Hemi-hydrogarnet, Hydroxyl oxide, Rietveld structure refinement, Antiferromagnetic

MSC2000: 

  • O641