ChemInform Abstract: The Gallides SrRh₂Ga₂, SrIr₂Ga₂, and Sr₃Ir₄Ga₄.

Abstract

The Gallides SrRh 2Ga2, SrIr2Ga2, and Sr3Ir4Ga4. -The title gallides are prepared from the elements by induction melting and subsequent annealing (Ta ampules, 800 mbar Ar, 873-1073 K, 4 d) and characterized by powder and single crystal XRD. SrRh 2Ga2 and SrIr2Ga2 crystallize in the orthorhombic space group Fddd with Z = 8 (CaRh 2B2-type structure). Sr3Ir4Ga4 crystallizes in the space group I43m with Z = 2 (Na 3Pt4Ge4-type structure). SrRh2Ga2 and Sr3Ir4Ga4 exhibit complex, covalently bonded three-dimensional [Rh 2Ga2] and [Ir4Ga4] networks with short Rh-Ga and Ir-Ga distances. Sr atoms fill large cages within these networks. The structure of SrRh2Ga2 is discussed along with the monoclinic distortion variants HoNi2B2 and BaPt 2Ga2 on the basis of a group-subgroup scheme. -(SEIDEL, S.; SCHUBERT, L.; HOFFMANN, R.-D.; POETTGEN*, R.; Z. Anorg. Allg. Chem. 641 (2015) 10, 1749-1754, http://dx.