Gas-phase electron-diffraction studies of the molecular structures of tetrachlorosulfidotungsten(VI), WSCl4, and tetrachloroselenotungsten(VI), WSeCl4

Article abstract of DOI:10.1021/ic00139a006

The molecular structures of WSCl₄ and WSeCl₄ have been studied by gas-phase electron diffraction at average nozzle temperatures of 200 and 220°C, respectively. The experimental data for both species are fitted by square-pyramidal models of C_4v symmetry in which the tungsten atom is slightly above the plane of the four chlorine atoms. The following principal distances (r_a), angles, and root-mean-square amplitudes of vibration (l) with estimated uncertainties of 2σ were obtained. WSCl₄: r(W=S) = 2.086 (6) A?, r(W-Cl) = 2.277 (3) A?, ∠SWCl = 104.2 (5)°, ∠ClWCl = 86.5 (2)°, l(W=S) = 0.031 (6) A?, l(W-Cl) = 0.058 (4) A?, l(S·Cl) = 0.147 (17) A?, l(Cl·Cl) = 0.114 (10) A?, l(Cl··Cl) = 0.120 (25) A?. WSeCl₄: r(W=Se) = 2.203 (4) A?, r(W-Cl) = 2.284 (3) A?, ∠SeWCl = 104.4 (3)°, ∠ClWCl = 86.5 (2)°, l(W=Se) = 0.055 (4) A?, l(W-Cl) = 0.060 (3)A?, l(Se·Cl) = 0.147 (9) A?, l(Cl·Cl) = 0.116 (8) A?, l(Cl··Cl) = 0.116 (19) A?. The similarities and differences of these structures, together with that of WOCl₄ available in the literature, are interpreted in terms of relative bond orders and nonbond repulsions.