Yu. S. Ezhov

Electron diffraction study of uranium trichloride

The trihalides of uranium are stable at extremely high temperatures and play an important part in the gas-phase reduction of uranium and the processing of uranium materials [ i]. However, there is a complete lack of published experimental information about the molecular constants of these molecules, which are required to calculate the optimum conditions for high temperature technological processes. Moreover, such information is of great interest in order to establish the laws governing the molecular structure of uranium halides of the type UHal n. We report below the results of an investigation of the structure of the uranium trichloride molecule by gas phase electron diffraction.

Molecular structure of hafnium and zirconium acetylacetonates M(C5H7O2)4

Electron diffraction and spectral data for hafnium and zirconium tetrakis(acetylacetonates) Hf(C5H7O2)4 and Zr(C5H7O2)4 are analyzed in terms of D2 symmetry of the geometrical configuration. Structural parameters and rms amplitudes of vibrations are determined. It is found that rg(Zr-O)=227.1(5) pm and rg(Hf-O)=226.5(5) pm.

Geometrical structure of the molybdenum tetrabromide molecule is nontetrahedral

Molecular structure of molybdenum tetrabromide has been studied by electron diffractometry. The geometrical configuration of MoBr4 has been shown to be of C2v symmetry. The following values of structural parameters have been obtained: Rg(MoBr1)=233.9(6) pm, Rg(MoBr2)=244.5(6) pm, β(Br1MoBr2)=106(1)o, and α(Br2MoBr3)=86(2)o. The frequency values of the vibrational spectrum have been estimated.

Determination of the molecular constants of tungsten tetrachloride from electron diffraction data

The structure of the molecule of tungsten tetrachloride has been studied by gaseous electron diffraction. Analysis of the ED data and calculations of the vibrational spectrum by Cyvins method showed that the WCI4 molecule has the equilibrium geometric configuration of a trigonal bipyramid (symmetry group Cav) with paired nonequivalent internuclear distances W--C1. The internuclear distances have been determined, and the frequencies of the vibrational spectrum calculated~

Study of the molecule of ammonium trithiocarbonate by gaseous electron diffraction

E. Clementi and H. Popkie, J. Chem. Phys., 57, 1077 r C. F. Bender, H. F, Schaefer Ill, D. R. Franceschetti, and L. C. Allen, J. Am. Chem. Sou. , 9 4 , 6 8 8 8 (1972). W. J . Hehre, R. F. S t ewar t , and J . A. Pop le , J . Chem. P h y s . , 51, 2657 (1969). R. D i t c h f i e l d , W. J . Hehre, and J . A. Pop le , J . Chem. P h y s . , 54, 724 (1971) . T. H. Dunning, J r . , J . Chem. P h y s . , 55, 716 (1971).

Sulution of the electron diffraction photographs of vapors allowing for the motion of the nuclei in the molecule

The relation between the asymmetry of the function representing the probabiliqr density of the distribution of pairs of nuclei in the molecule and the special characteristics of the; corresponding terns ~.n the molecular component of electron-scattering intensity is considered. Rel.~atons are obtained for use in solving electron-diffraction photographs when the motion of the pairs oll nuc~el in the molecule under consideration has a substantial asymmetry.