Some electron diffraction studies. I. Electron diffraction studies of some heavy metal hexaflourides. II. The molecular structure of gaseous N2O4. III. Applications of the method of least squares in electron diffraction investigations

Citation

Smith, Darwin W. (1959) Some electron diffraction studies. I. Electron diffraction studies of some heavy metal hexaflourides. II. The molecular structure of gaseous N2O4. III. Applications of the method of least squares in electron diffraction investigations. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/A9G6-3H34. https://resolver.caltech.edu/CaltechETD:etd-02132006-132126

Abstract

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Part I. An electron diffraction investigation has been made by the sector-microphotometer method of WF6, OsF6, IrF6, UF6, NpF6 and PuF6. The photographs of all these compounds exhibit a phase shift anomaly which gives rise to apparently assymetric structures, the anomaly setting in at smaller angles [...] of scattering for the heavier molecules and at smaller values of q = (40/[...])sin [...]/2 the greater the electron wavelength. There is good evidence for the symmetrical octahedral structure of all the compounds. The metal-fluorine distances were found to be (in Angstrom units) l.833(W-F), l.831(Os-F), l.830(Ir-F), 1.996(U-F), l.981(Np-F), and l.971(Pu-F).

Part II. An electron diffraction molecular structure determination of gaseous N2O4 has shown that the N-O distance, the N-N distance, and the ONO bond angle are 1.177 A, 1.752 A, and 134.8° respectively. The molecule is planar, which is surprising in view of the long N-N bond.

Part III. A structure refinement procedure, which was applied to the above compounds, has been programmed for the Burroughs 205 computer. It involves the fitting of a theoretical intensity curve to the experimental one.

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