Neutral Compounds with Xenon-Germanium Bonds: A Theoretical Investigation on FXeGeF and FXeGeF3

The structure and stability of FXeGeF and FXeGeF3 were investigated by MP2, CCSD(T), and B3LYP calculations, and their bonding situation was examined by NBO and AIM analysis. These molecules are thermochemically stable with respect to dissociation into F + Xe + GeFn (n = 1, 3), and kinetically stable with respect to dissociation into Xe + GeFn+1, thus suggesting their conceivable existence as metastable species. FXeGeF and FXeGeF3 are best described by the resonance structures F-(Xe-GeF+) and F-(Xe-GeF3+), and feature essentially ionic xenon-fluorine interactions. The xenon-germanium bonds have instead a significant contribution of covalency. The comparison with XeGeF+ and XeGeF3+ suggests that the stability of FXeGeF and FXeGeF3 arises from the F--induced stabilization of these ionic moieties. This structural motif resembles that encountered in other noble-gas neutral and ionic species.