The crystallographic analysis of InMn3, a new form of γ‐brass structure with a P cell
The crystallographic analysis of InMn3, a new form of γ‐brass structure with a P cell
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InMn3（一种具有 P 晶胞的新型 γ-黄铜结构）的晶体学分析
DOI：
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发表时间：
1979
期刊：
影响因子：
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通讯作者：
W. B. Pearson
中科院分区：
文献类型：
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作者：
J. K. Brandon;H. S. Kim;W. B. Pearson
Single-crystal X-ray diffraction experiments have shown that the alloy of composition InMn a has a 7brass-type structure with space group P43m and roomtemperature cubic cell constant a = 9.420 + 0.004 A. At the relatively large atomic-radius ratio Rtn/RMn 1.3 the In atoms occupy nearly completely the cubooctahedral (CO) sites of one of the two clusters of 26 atoms which make up the 52-atom primitive unit cell (P cell). In atoms also partially occupy the octahedral (OH) sites of the same cluster. This distribution of the large and small constituent atoms represents a newly discovered type of atomic ordering for P-ceU ?-brass structures, which gives an improved packing fraction for a large radius ratio when the larger In atoms order in OH and CO sites rather than inner tetrahedral (IT) and CO sites, and furthermore the ordering in a P cell reduces the number of In-In contacts. Previously published powder intensity data for the hightemperature ?-Cu-In phase, which also has a relatively large radius ratio of Rin/Rcu ~ 1.3, is shown to be consistent with calculations for a model structure with a P cell and with large In and small Cu atoms adopting the InMn a type of ordering.
