Crystal and molecular structure of cesium isothiocyanatotrimethylaluminate, Cs[Al(CH₃)₃NCS]

The crystal structure of the title compound has been determined from three-dimensional X-ray diffraction data, and refined by full-matrix least-squares techniques. The crystals belong to the monoclinic space group P2₁/c, with a = 8.849(4), b = 13.798(5), c = 7.943(4) Å, β = 102.98(3) °, and D_x = 1.85g cm^-3 for Z = 4. The final R factor for 1283 observed reflections is 0.046. The aluminum atom is bonded to the nitrogen atom of the thiocyanate ligand, where the Al-N bond length is 1.94(1) Å. The SCN is linear, and the C≡N-Al angle is 175(1) °. The cesium ion exhibits four contacts less than 3.60 Å: Cs ⋯ C(thiocyanate) = 3.39(1) Å, Cs ⋯ C(methyl) = 3.52(1) Å, Cs ⋯ C.(methyl) = 3.56(1) Å, and Cs ⋯ N = 3.575(9) Å. The closest Cs ⋯ S is 3.772(3) Å.