The Re 3 B type, space group Cmcm , has boron-centered trigonal prisms as central building units and is one of the basic structure types with numerous binary and ternary representatives. The coloring of different atoms on the two crystallographically independent rhenium sites leads to a manifold of compounds with different bonding peculiarities that are rather isopointal than isotypic with the prototype. Typical compounds are the S -phase precipitate MgCuAl 2 , the silicide ScPt 2 Si or the iodide Th 0.5 Pb 0.5 I 3 (PuBr 3 type). Differences in size or composition might force symmetry reductions. This is discussed for YZn 3 (space group Pnma ) and the different coloring variants ScRhSi 2 and TaNi 2 P which show different twists of the trigonal prisms. Striking singular representatives with lower symmetry structures are BaThBr 6 ( Pmma ) and NbCo 2 B ( P 2 1 / c ) which allow different ordering/distortion patterns for the prisms. All these crystal chemical details are discussed on the basis of group subgroup schemes (Bärnighausen trees).

中文翻译：

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Re3B类型的颜色变体

Re 3 B型空间群Cmcm具有以硼为中心的三棱柱作为中心建筑物单元，并且是具有众多二元和三元代表的基本结构类型之一。在两个在晶体学上独立的sites位点上不同原子的着色导致了具有不同键合特性的多种化合物，这些键合特性与原型相比是等位的，而不是同型的。典型的化合物是S相沉淀MgCuAl 2，硅化物ScPt 2 Si或碘化物Th 0.5 Pb 0.5 I 3（PuBr 3型）。大小或组成的差异可能会导致对称性降低。对于YZn 3（空间群Pnma）以及不同的着色变体ScRhSi 2和TaNi 2 P进行了讨论，这些变体显示了三棱柱的不同扭曲。具有较低对称结构的醒目的奇异代表是BaThBr 6（Pmma）和NbCo 2 B（P 2 1 / c），它们可以为棱镜提供不同的排序/失真模式。所有这些晶体化学细节均在组子组方案（Bärnighausen树）的基础上进行了讨论。