An timony( III ) acetate and thioacetate: spectra and crystal structures
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Antimony(III) tris(monothioacetate) has been prepared from thioacetic acid and antimony(III) oxide as a water-stable compound, in contrast to the extreme instability to water of the analogous triacetate. X-Ray structure determinations, however, show similar molecular structures for the two compounds. Crystals of antimony triacetate are monoclinic, space group P21, Z = 2, with a = 7.463(5), b = 9.346(5), c = 7.740(5) Å, and β = 116.20(5)°, whereas those of antimony tris(monothioacetate) are monoclinic, space group P21/c, Z = 4, with a = 8.884(5), b = 16.819(5), c = 8.964(5) Å, and β = 117.26(5)°. Primary bonding in the former is to three oxygen atoms (mean Sb-O, 2.06 Å) but to three sulphur atoms (mean Sb-S, 2.47 Å) in the latter. Vibrational spectra suggest the presence of secondary bonding in both compounds, which has been confirmed by the observation of three weak intramolecular interactions (Sb-O, 2.596-2.775 Å in the acetate and 2.745-2.918 Å in the thioacetate). One of the ligands, in addition to behaving as a chelate, bridges between molecules (Sb-O, 2.600 and 3.043 Å for the acetate and thioacetate respectively) leading to polymeric chains in the solid. The overall co-ordination polyhedron, which includes the stereochemically active lone pair, is best described in terms of a distorted dodecahedron.
author list (cited authors)
Hall, M., & Sowerby, D. B.