On the electron affinities of hexafluorides CrF6, MoF6, and WF6

The adiabatic electron affinities (EAs) of MF6 and MF−6 (M=Cr, Mo, and W) are calculated in a configuration interaction (CI) calculation using a model potential method. The calculated EA of 3.85 eV for WF6 agrees well with the observed values. The difference (1.52 eV) between the calculated EA of MoF6 and that of WF6 shows also a very good agreement with the experimental ones. CrF6 has a very high EA of 8.24 eV. The CrF−6 anion has positive EA and the CrF2−6 dianion is thus most stable in the CrFq−6 (q=0, 1, and 2) sequence, while WF−6 does not have a positive EA. The EAs of MF6 calculated by CI calculations are smaller than those by SCF calculations. This negative correlation effect on the AEs is also discussed.