In the previous post, I looked[cite]10.59350/xp5a3-zsa24[/cite] at the recently reported[cite]10.1021/ja02261a002[/cite] hexa-arylethane containing a carbon-carbon one-electron bond, its structure having been determined by x-ray diffraction (XRD). The measured C-C bond length was ~2.9aÅ and my conclusion was that the C…C region represented more of a weak “interaction” than of a bond as such. How about a much simpler system, hexafluoroethane? Here, the two-electron C-F bonds are much lower in energy than the C-C bond, so when the molecule is ionised, it escapes from the C-C bond rather than any of the C-F bonds. The below is the structure computed at the ωB97XD/Def2-TZVPP level, revealing a much shorter C-C bond of 2.149Å. The computed C-C stretching vibrational frequency is 179 cm-1 (FAIR data DOI: [cite]10.14469/hpc/14642[/cite])