Hydrogen Bonding in Polyfluoride Ions

Hydrogen bonding in the polyfluoride ions (HnFn+1−, n=1 to 4) has been discussed in the light of atomic charges, bond ionicities, valencies and bond indices calculated from CNDO/2 wave functions. The hydrogen-bond energy in these ions is found to bear a qualitative relation with the bond index of the hydrogen bond.