Neue ternäre Boride der Erdalkalimetalle mit Rhodium und Iridium /New Ternary Borides of the Alkaline Earth Metals with Rhodium and Iridium

Abstract

The ternary borides SrRh2B2, SrIr2B2, BaRh2B2, BaIr2B2 and Ba7lr12Bi12 were prepared and structurally characterized. The crystallographic data are (pm): SrRh2B2 : Fddd, a = 1067.2, b= 939.9, c =598.9, Z = 8. SrIr2B2 : Fddd, a = 1072.3, b = 940.4, c =602.7, Z = 8. BaRh2B2 : I4/mmm, a = 391.5, c = 1125.0, c/a = 2.874, Z = 2. BaIr2B2 : I4/mmm, a = 393.5, c = 1140.7, c/a = 2.899, Z = 2. Ba7Ir12Bi12 : R3̄m, a = 1522.2, c = 835.8, c/a = 1.821, Z = 3. SrIr2B2 and SrRh2B2 are isostructural with CaIr2B2 and CaRh2B2, while BaRh2B2 and BaIr2B2 crystallize in the ThCr2Si2-type. Ba7lr12Bi2 has a new structure which contains structural elements of the compound SrIr2B2.