Molecular Structure of Lithium Chloride Dimer. Thermodynamic Functions of Li2X2 (X = Cl, Br, I)

Our electron diffraction apparatus has been suitably modified for the study of vapors at high temperatures. A furnace and auxiliary power supply have been constructed, and a serviceable design for a sample container, with a nozzle, has been developed. Data on two systems have been obtained. The diffraction pattern produced by cesium chloride vapor is that expected for a diatomic molecule; the interatomic distance determined in this experiment checks with the microwave value. In lithium chloride vapor, dimers predominate. Their structure is diamond shape (planar) with Li–Cl=2.23±0.03 ACl–Cl=3.61±0.03 A∠ClLiCl=108∘±4∘. The dimensions of the lithium halide dimers are compared and their thermodynamic functions tabulated.