Crystal structure and molecular geometry of 3-ethyl-3-alumina-1,2-dicarba-closo-dodecaborane (12), 1,2-B9C2H11AlEt

Abstract

The title compound crystallizes in the orthorhombic space-group Pnma(D_2h¹⁶; No. 62) with a= 16·304(15), b= 7·533(7), c= 9·398(6)Å, and Z= 4. A three-dimensional single-crystal X-ray structural analysis based on counter data has led to the location of all atoms save ethyl hydrogens. The structure was solved by Patterson and Fourier methods and refined by least-squares techniques to R 8·49% for 499 independent non-zero reflections. The crystal consists of discrete, well separated, molecular units of 1,2-B₉C₂H₁₁AlEt in which the aluminium atom is σ-bonded to an ethyl group and is linked symmetrically to the open B₃C₂ face of a dicarba-nido-undecaborane ligand.