Synthesis and structure of ACa9(VO4)7 compounds, A = Bi or a rare earth
Synthesis and structure of ACa9(VO4)7 compounds, A = Bi or a rare earth
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DOI：
10.1006/jssc.2000.9045
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发表时间：
2001-03
影响因子：
3.3
通讯作者：
John S. O. Evans;Jinfan Huang;A. Sleight
中科院分区：
文献类型：
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作者：
John S. O. Evans;Jinfan Huang;A. Sleight
已经制备了ACA{sub9}(VO{sub4}){sub7}类型的相，其中A可以是三价稀土阳离子或Bi{sup3+}。由单晶X射线衍射数据确定了BICA{sub9}(VO{sub4}){sub7}的结构。在120K，Z=6时，空间群为R3，a=10.8511(2)，c=38.0505(9)。其结构与Ca{sub3}(VO{sub4}){sub2}的结构有关，但在Bica{sub9}(VO{sub4}){sub7}中，部分被Ca占据的位置是完全空的。所有制备的ACA{sub9}(VO{sub4}){sub7}相均表现出明显的二次谐波信号。对于稀土化合物，信号的大小与KH{sub2}PO{sub4}相当；Bica{sub9}(VO{sub4}){sub7}的信号值高出三倍。
Phases of the type ACa{sub 9}(VO{sub 4}){sub 7} have been prepared where A can be a trivalent rare earth cation or Bi{sup 3+}. The structure of BiCa{sub 9}(VO{sub 4}){sub 7} was determined from single crystal X-ray diffraction data. The space group is R3 with a=10.8511(2) and c=38.0505(9) at 120 K and Z=6. The structure is related to that of Ca{sub 3}(VO{sub 4}){sub 2}, but a site partially occupied by Ca in Ca{sub 3}(VO{sub 4}){sub 2} is completely vacant in BiCa{sub 9}(VO{sub 4}){sub 7}. All the ACa{sub 9}(VO{sub 4}){sub 7} phases prepared showed a significant second harmonic signal. For the rare-earth compounds, the magnitude of the signal was comparable to that of KH{sub 2}PO{sub 4}; a value three times higher was found for BiCa{sub 9}(VO{sub 4}){sub 7}.