首页 | 本学科首页   官方微博 | 高级检索  
     检索      


Rb5Hg19: Eine neue,geordnete Defektvariante des BaAl4‐Strukturtyps
Authors:E Biehl  H J Deiseroth
Abstract:Rb5Hg19: A New Defect Variant of the BaAl4 Structure Type The hitherto unknown, silver metallic, air sensitive Rb5Hg19 can be prepared directly from the elements. It crystallizes tetragonally with lattice constants a = 1156.1 pm, c = 1051.0 pm (Z = 2, space group I4/m, No. 87, melting temperature 467 K) in a new defect variant of the BaAl4 structure type. The structure is based on distorted 44 nets of Hg4 rectangles and squares forming rectangular and square pyramids together with additional Hg atoms. The vertices of the pyramids point in alternate directions with respect to 001]. Opposite vertices show relatively short contacts dHg–Hg = 292.3 pm along 001]. The defect character of the Rb5Hg19 structure shows up by single Hg atoms substituting each fifth Hg–Hg group in an ordered way and serving as common vertices for two subsequent square pyramids along 001]. The replacement of Hg–Hg groups by single Hg atoms explains the vertical and horizontal distortions of the 44 nets and explains the differences of the Rb coordination with respect to Ba (bicapped tetragonal hexagonprism) in the BaAl4 type, in which a hypothetical RbHg4 could eventually crystallize. The symmetry relations of Rb5Hg19 and α‐La3Al11 (the only defect variant of BaAl4 except Rb5Hg19) to the aristo type BaAl4 are discussed.
Keywords:Mercury  Rubidium  Alloy  Amalgam  Crystal structure
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号