Molecular structures of the sixth period metal pentachlorides, MCl5 (M = Ta, W or Re), determined by gas electron diffraction; is Jahn–Teller distortion of WCl5 quenched by spin–orbit coupling?
1997; Royal Society of Chemistry; Issue: 6 Linguagem: Inglês
10.1039/a604314c
ISSN2050-5671
AutoresKnut Fægri, Arne Haaland, Kjell-Gunnar Martinsen, T. G. Strand, Hans V. Volden, Ole Swang, Carlaxel Anderson, Christina Persson, Sandra Bogdanović, Wolfgang A. Herrmann,
Tópico(s)Crystallography and molecular interactions
ResumoThe molecular structure of TaCl 5 has been optimised under D 3h symmetry by density-functional theory calculations. Calculation of the molecular force field and vibrational frequencies showed that the optimised structure corresponds to a minimum on the full potential energy surface. Gas electron diffraction data of MCl 5 (M = Ta, W or Re), recorded with nozzle temperatures ranging from 130 to 210 °C, showed that WCl 5 and ReCl 5 are trigonal bipyramidal like TaCl 5 . Structure refinements based on molecular models of D 3h symmetry lead to satisfactory agreement between experimental and calculated intensities for each compound and yield the M–Cl bond distances (ax/eq): Ta 231.3(5)/226.6(4); W 229.1(4)/224.1(5); Re 226.2(12)/223.7(7) pm. Tungsten pentachloride is a d 1 compound and might have exhibited dynamic or static Jahn–Teller distortion from D 3h symmetry; it has been suggested that such distortion is quenched by strong spin–orbit coupling.
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