Molecular Structures of Perfluoromethyl Iodide, Perfluoroethyl Iodide, and Perfluoroisopropyl Iodide

Abstract

The molecular structures of three fully halogenated alkanes have been investigated by electron diffraction. The following r_g parameters were determined for CF₃I: C–I=2.101±0.009 Å; C–F=1.344±0.004 Å; and ∠FCI=111.3°±0.4°. For CF₃CF₂I: C–I=2.142±0.023 Å; C–F=1.338±0.004 Å; C–C=1.523±0.027 Å; with ∠CCI=113.4°±0.8°; ∠CCF=109.9°±0.8°; and ∠ICF=109.4°±1.0°. The r_g parameters determined for (CF₃)₂CFI are: C–I=2.139±0.017 Å; C–F=1.338±0.003 Å; C–C=1.554±0.012 Å; ∠CCF=111.0°±0.4°; ∠ICF=111.8°±1.4°; ∠CCI=109.4°±0.6°; and ∠CCC=113.2°±1.2°. These are thermally averaged (nearly harmonic approximation) values.