Crystal structures of MgCoGa, Mg_0.74CoGa_0.52 and Mg_0.49CoGa_0.15 phases from the Mg–Co–Ga system were investigated using single-crystal diffraction. These structures belong to the family of so-called Laves phases. Hexagonal MgCoGa crystallizes as a disordered phase within the MgZn₂ structure type. The orthorhombic structure of Mg_0.74CoGa_0.52 is a distortion variant of MgZn₂ and URe₂ structure type, and the structural relation is demonstrated in terms of a Bärnighausen formalism group–subgroup transformation scheme. The structure of trigonal phase Mg_0.49CoGa_0.15 is strongly disordered, as is shown by the presence of adjacent atomic sites which cannot be occupied simultaneously. In Mg_0.49CoGa_0.15, two subcells (A and B) were obtained in a ratio of 9:1. Subcell A is closely related to MgZn₂-type.

中文翻译：

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Mg-Co-Ga 系 Laves 相的新三元衍生物

使用单晶衍射研究了 Mg-Co-Ga 体系中MgCoGa、Mg _0.74 CoGa _0.52和 Mg _0.49 CoGa _0.15相的晶体结构。这些结构属于所谓的拉夫斯相家族。_{六方MgCoGa结晶为MgZn 2}结构类型内的无序相。_{Mg 0.74} CoGa _0.52的斜方结构是MgZn ₂和URe ₂结构类型的畸变变体，其结构关系通过Bärnighausen形式群-子群变换方案得到证明。_{三角相Mg 0.49} CoGa _0.15的结构是高度无序的，这可以通过不能同时占据的相邻原子位点的存在来证明。在Mg _0.49 CoGa _0.15中，以9:1的比例获得两个子电池（A和B）。_{亚晶胞A与MgZn 2}型密切相关。