Neutron powder diffraction on Ce11B2C2 and Nd11B2C2:: A new model for the tetragonal crystal structure
Neutron powder diffraction on Ce11B2C2 and Nd11B2C2:: A new model for the tetragonal crystal structure
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DOI：
10.1143/jpsj.68.2287
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发表时间：
1999-07-01
影响因子：
1.7
通讯作者：
Yamaguchi, Y
中科院分区：
文献类型：
--
作者：
Onimaru, T;Onodera, H;Yamaguchi, Y
用中子粉末衍射法研究了CeB_2C_2和NdB_2C_2的晶体结构。（CeB_2C_2）-B-11和（NdB_2C_2）-B-11的衍射图非常相似，Rietveld分析表明晶体结构属于四元P4/mbm对称群。其中稀土原子占据2（a）位，B和C原子占据两个4（h）位，具有不同的位置参数。新确定的结构不同于以前报道的P4/mbm和P（4）在酒吧2c主要是在由B和C原子占据的网站的位置。B和C原子形成由不规则正方形和八边形组成的网络平面。
Crystal structures of CeB2C2 and NdB2C2 were investigated by means of neutron powder diffraction using B-11 enriched samples. Diffraction patterns of (CeB2C2)-B-11 and (NdB2C2)-B-11 are very similar to each other, and Rietveld analyses reveal that the crystal structure belongs to a symmetry group of tetragonal P4/mbm. where the rare earth atoms occupy 2(a) sites and the B and C atoms occupy two 4(h) sites with different positional parameters. The newly determined structure differs from previously reported ones with P4/mbm and P (4) over bar 2c mainly in the site positions occupied by the B and C atoms. The B and C atoms form network planes consisting of non-regular squares and octagons.