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[M] A novel boron-rich quaternary scandium borocarbosilicide Sc3.67−xB41.4−y−zC0.67+zSi0.33−w オンラインリソース

著者: (出版日: 2003-09-25)

コレクション: NIMS成果物
形態: オンラインリソース オンラインリソース
言語: 不明
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A novel quaternary scandium borocarbosilicide Sc3.67−xB41.4−y−zC0.67+zSi0.33−w was found. Single crystallites were obtained as an intergrowth phase in the float-zoned single crystal of Sc0.83−xB10.0−yC0.17+ySi0.083−z that has a face-centered cubic crystal structure. Single crystal structure analysis revealed that the compound has a hexagonal structure with lattice constants a = b = 1.43055(8) nm and c = 2.37477(13) nm and space group P-6m2 (No. 187). The crystal composition calculated from the structure analysis for the crystal with x = 0.52, y = 1.42, z = 1.17, and w = 0.02 was ScB12.3C0.58Si0.10 and that agreed rather well with the composition of ScB11.5C0.61Si0.04 measured by EPMA. In the crystal structure that is a new structure type of boron-rich borides, there are 79 structurally independent atomic sites, 69 boron and/or carbon sites, two silicon sites and eight scandium sites. Boron and carbon form seven structurally independent B12 icosahedra, one B9 polyhedron, one B10 polyhedron, one irregularly shaped B16 polyhedron in which only 10.7 boron atoms are available because of partial occupancies and 10 bridging sites. All polyhedron units and bridging site atoms interconnect each other forming a three-dimensional boron framework structure. Sc atoms reside in the open spaces in the boron framework structure.