Synthesis and structures of samarium platinum germanides: SmPtGe 2 and Sm 2Pt 3Ge 5

Abstract

We performed single-crystal structure analysis of two ternary samarium platinum germanides SmPtGe 2 and Sm 2Pt 3Ge 5. SmPtGe 2 crystallizes in the space group (S.G.) Immm (no. 71) with a = 4.3679(9) Å, b = 8.728(2) Å, c = 16.378(4) Å, and V = 624.4(2) Å 3. This compound is isotypic with YIrGe 2 having a Ge 10Pt 4 subunit composed of edge-sharing five- and six-membered rings. SmPtGe 2 shows a metallic conductivity from room temperature down to 2 K. The magnetic susceptibility measurement showed a 3+ oxidation state for the samarium. Sm 2Pt 3Ge 5 crystallizes in the S.G. Ibam (no. 72) with a = 10.174(1) Å, b = 11.761(2) Å, c = 6.2142(8) Å, and V = 743.6(2) Å 3. It is isotypic with U 2Co 3Si 5 with a structure closely related to ThCr 2Si 2.