The synthesis and structure of the new phase Ca0.85CuO2
The synthesis and structure of the new phase Ca0.85CuO2
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新相Ca0.85CuO2的合成与结构
DOI：
10.1016/0025-5408(91)90190-w
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发表时间：
1991
影响因子：
5.4
通讯作者：
C. Greaves
中科院分区：
文献类型：
--
作者：
T. Babu;C. Greaves
合成了一种新相Ca0.85CuO2，并用粉末X射线和中子衍射仪对其进行了研究。这种结构与NaCuO_2的结构密切相关，具有边共享的CuO_4单元链，连接着八面体配位的钙离子层，但钙中心的部分占据导致了无公度的超结构。基于正交子晶胞(Fmmm；a=6.3206，b=2.8067，c=10.5735？)的结构细化揭示了超结构产生的可能机制。具有单斜晶系对称性和组成CaCuO2的区域被Ca空位的边界与CuO4链倾斜相反方向的相邻区域隔开。
A new phase, Ca0.85CuO2, has been synthesised and investigated using powder X-ray and neutron diffraction. The structure is closely related to that of NaCuO2with chains of edge-shared CuO4units linking layers of octahedrally coordinated Ca ions, but partial occupancy of the Ca sites results in an incommensurate superstructure. Structure refinement based on an orthorhombic subcell (Fmmm;a=6.3206,b=2.8067,c=10.5735 Å) has revealed a possible mechanism for the occurrence of the superstructure. Regions of monoclinic symmetry and composition CaCuO2are separated by boundaries of Ca vacancies with adjacent domains having CuO4chains tilted in opposite directions.