The superposition model is used to determine single-ligand spin-Hamiltonian parameters for Eu2+ in a range of host crystals. The properties of these parameters are shown to be generally similar to those of the corresponding parameters for Gd3+, although some striking differences occur in their relative magnitudes and distance dependence. Both the similarities and the differences confirm aspects of a previous interpretation of the spin-Hamiltonian parameters for f7 8S7/2 ground states.