Alkaline Earth Transition Metal Antimonides AT₄Sb₁₂ (A = Ca, Sr, Ba; T = Fe, Ru, Os) with LaFe₄P₁₂‐Structure

Abstract

Abstract The title compounds were prepared by reaction of CaSb 2 , SrSb 2 , or BaSb 3 with the transition metals and antimony in sealed silica tubes. They crystallize with the cubic LaFe 4 P 12 ‐structure, which was refined from single‐crystal X‐ray data of CaFe 4 Sb 12 , SrRu 4 Sb 12 , and BaRu 4 Sb 12 to residuals of R = 0.014, 0.016, and 0.014, respectively. The thermal parameters of the alkaline earth ions increase with decreasing ionic size. The SbSb distances are greater in the iron compound than they are in the two ruthenium compounds. This is rationalized to be due to a larger portion of electrons in antibonding SbSb states in the iron compound.