where the repulsive and attractive part are simple exponential functions similar to those in the Morse potential. However, the strength is modified by the environment of the atom i via the b i j k term. If implemented without an explicit angular dependence, these potentials can be shown to be mathematically equivalent to some varieties of EAM-like potentials Thanks to this equivalence, the bond-order potential formalism has been implemented also for many metal-covalent mixed materials.