Andy Extance at the Chemistry World blog has picked up on a fascinating article on the dimer of SF2. This molecule has three F atoms on one S, and only one on the other; FSSF3. But all four S-F bonds are of different length. Lindquist and Dunning claim that the minimum energy pathway to dissociation to two SF2 molecules does not involve breaking either the longest or the weakest SF bond. This was too much for me to resist investigating further!
- B.A. Lindquist, and T.H. Dunning, "Bonding in FSSF3: Breakdown in Bond Length-Strength Correlations and Implications for SF2Dimerization", The Journal of Physical Chemistry Letters, vol. 4, pp. 3139-3143, 2013. http://dx.doi.org/10.1021/jz401578h