Crystal structure of the metal-rich phosphide Sm15Ir33P26

Abstract

Abstract The new metal-rich phosphide Sm15Ir33P26 was obtained from a reaction of the elements in a lead flux (1 : 2 : 2 : 30 molar ratio, 1370 K, slow cooling rate). Sm15Ir33P26 adopts a new structure type which was characterized by powder and single crystal X-ray data: C2/m, a = 4720.6(8), b = 392.87(9), c = 1329.2(2) pm, β = 95.478(1)°, wR2 = 0.0376, 3757 F 2 values and 227 variables. The iridium and phosphorus atoms build up a complex three-dimensional [Ir33P26] δ– polyanionic network in which the samarium atoms fill diverse larger cavities with coordination numbers of 15–17. The seventeen crystallographically independent iridium atoms have between 3 or 4 phosphorus neighbors in distorted trigonal-, square-planar, or tetrahedral coordination. All phosphorus atoms are isolated and most of them fill tri-capped trigonal prisms. The Sm15Ir33P26 structure is an intergrowth variant of ThCr2Si2, SrPtSb, CeMg2Si2, and TiNiSi-related slabs.