Electron Diffraction and the Molecular Structure of Gases. The Crystal Structure of Chalcopyrite

An apparatus has been developed for the study of the molecular structure of gases by the electron diffraction method. A number of improved features in the construction are described. The method has been applied to an investigation of the resonance among the possible electronic structures of the Lewis type and also of the atomic configurations in certain molecules. Diacetylene and cyanogen are found to be linear, contrary to a published report of evidence for a model with 150° bond angles. Methyl azide is found to have a linear azide group. The ring model which has been proposed is shown to be eliminated. The ring model for carbon suboxide has also been eliminated in favor of a linear model. Chlorine dioxide shows evidence for the existence of the three-electron bond, and this fact explains its lack of tendency to polymerize to Cl2O4. The hexafluoride of sulfur, selenium and tellurium are found to have structures which may be represented by a regular octahedron with six atoms at the corners surrounding the central atom. The interatomic distances for all of the above compounds are reported. The crystal structure of chalcopyrite has been re-investigated and the correct structure is reported.