Single-crystal structure determination of two new ternary bis­muthides: Rh(6)Mn(5)Bi(18) and RhMnBi(3)

A study of the ternary Rh–Mn–Bi phase diagram revealed the existence of two new ternary bis­muthides, viz. hexa­rhodium penta­manganese octa­deca­bis­muthide (Rh(6)Mn(5)Bi(18)) and rhodium manganese tribismuthide (RhMnBi(3)). Their crystal structures represent new structure types. Rh(6)Mn(5)Bi(18), with a Wyckoff sequence a f2 g2 i5, crystallizes in the tetra­gonal system (space group P4(2)/mnm; Pearson symbol tP58), and RhMnBi(3), with a Wyckoff sequence a c g i q, crystallizes in the ortho­rhom­bic system (Cmmm; oS20). In the Rh(6)Mn(5)Bi(18) structure, the transition metal atoms are linked into ribbon-like structural units aligned along the [001] direction, whereas planar sheets are formed in RhMnBi(3). In both crystal structures, the units formed by the transition metal atoms are enveloped by Bi atoms, which themselves form a loosely bound network. The linkage results in a layer structure for RhMnBi(3), while in the case of Rh(6)Mn(5)Bi(18), a three-dimensional network is formed; the latter, however, contains several areas where Bi⋯Bi distances suggest van der Waals inter­actions. Both phases under discussion have analogous structural motifs.