GAS ELECTRON-DIFFRACTION STUDY OF THE MOLECULAR-STRUCTURE OF NBCL4

The structure of the NbCl4 molecule is studied experimentally by the s ynchronous electron diffraction and mass spectrometry methods. The mod el molecular geometries of C-2 upsilon, C-3 upsilon, D-2d, and T-d sym metries are verified. The advantages of the tetrahedral model over the other models are established. The thermally averaged parameters of th e effective configuration of the NbCl4 molecule are as follows: r(g)(N b-CI) = 2.279(5) Angstrom, I(Nb-CI) = 0.073(2) Angstrom, r(g)(Cl-Cl) = 3.692(17) Angstrom, l(CI-CI) = 0.275(11) Angstrom, L-g(CI-Nb-CI) = 10 8.2(5)degrees, and delta(CI-CI) = 0.030(19) Angstrom.