by Gas-Phase Electron Diffraction

diffraction. The experimental data were found to be consistent with a D3 model in which the oxygen atoms from the three ligands are arranged in a slightly distorted octahedron about the chromium atom (OCrO for the ligand = 87.0 (1.4)O). The chromium-oxygen bond length obtained (Cr-0 = 1.957 (8) A) is in close agreement with the value obtained previously by x-ray diffraction for the acetylacetonato com lex of chromium [Cr-0 = 1.951 (7) A]. Structural parameters for the ligand (C-O = 1.270 (6) A, CC, = 1.409 (14) 1, C-CF3 = 1.559 (9) A, and C-F = 1.338 (3) A) are in excellent agreement with the values obtained in an earlier electron diffraction of the Cu(I1) complex with hexafluoroacetylacetone. The experimental structure obtained was found to be inconsistent with a very successful stereochemical model for predicting the geometries of metal atom complexes involving bidentate ligands.