. These calculations, however, had to be performed using PBE-based orbitals, as the usage of HF based orbitals resulted in unphysically large shifts. This approach is well suited as it introduces only marginal deviations from HF-based results for all other species (see Table ). Finally, for [FAl(µ-O)2AlF] 0 the Al-F stretches are found at 1015 cm -1 (sym) and 966 cm -1 (asym), the Al-O2-Al stretches at 691 cm -1