Electron-diffraction studies on the In-I system. IV. Geometrical configuration, vibrational frequencies, and molecular energetics for indium iodide

Abstract

A survey is presented on electron diffraction by Inl, In13, In21~, Inlnl 4 and on the vapor compositions above indium monoiodide, diiodide, and triiodide. The molecular structures are examined and relationships are derived between the structure parameters. Estimates are made for the lacking vibrational frequencies of In21s, and band assignments are made for Inlnl 4. The electron-diffraction data give the enthalpy and entropy of 21nl 3 $ !n216 and Inl + Inl 3 $ InInl~, from which the heats of formation of gaseous In216 and Inlnl~ can be calculated. These molecules show a correlation between the mean bond energies and the structural characteristics. Heats of reaction are derived for reactions involving indium io ~ dides.