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

The molecular structures of three fully halogenated alkanes have been investigated by electron diffraction. The following rg 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 rg 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.