Pentaterbium lithium tristannide, Tb5LiSn3

Abstract

The new ternary phase penta­terbium lithium tris­tannide, Tb5LiSn3, crystallizes in the hexa­gonal Hf5CuSn3 structure type, which is a ‘filled’ version of the binary RE 5Sn3 phases (Mn5Si3-type) (RE is rare earth). The asymmetric unit contains two Tb sites (site symmetries 3.2 and m2m), one Li site (site symmetry .m) and one Sn site (site symmetry m2m). The 14-vertex Frank–Kasper polyhedra are typical for Li and Tb atoms. The environment of the Sn atom is a pseudo-Frank–Kasper polyhedron with a coordination number of 13 for the tin atom. One of the Tb atoms is enclosed in a 17-vertex polyhedron. The metallic type of bonding was indicated by an analysis of the inter­atomic distances.