Crystal structure of the ternary silicide Gd(2)Re(3)Si(5)

A single crystal of the title compound, the ternary silicide digadolinium trirhenium penta­silicide, Gd(2)Re(3)Si(5), was isolated from an alloy of nominal composition Gd(20)Re(30)Si(50) synthesized by arc melting and investigated by X-ray single-crystal diffraction. Its crystal structure belongs to the U(2)Mn(3)Si(5) structure type. All atoms in the asymmetric lie on special positions. The Gd site has site symmetry m..; the two Mn atoms have site symmetries m.. and 2.22; the three Si atoms have site symmetries m.., ..2 and 4.. . The coordination polyhedra of the Gd atoms have 21 vertices, while those of the Re atoms are cubo­octa­hedra and 13-vertex polyhedra. The Si atoms are arranged as tricapped trigonal prisms, bicapped square anti­prisms, or 11-vertex polyhedra. The crystal structure of the title compound is also related to the structure types CaBe(2)Ge(2) and W(5)Si(3). It can be represented as a stacking of Gd-centred polyhedra of composition [GdSi(9)]. The Re atoms form infinite chains with an Re—Re distance of 2.78163 (5) Å and isolated squares with an Re—Re distance of 2.9683 (6) Å.