83.0 pm, but the bond length of B–B in B2Cl4 is 175 pm, a significantly larger value. This would indicate that the bond between the two boron atoms is a rather weak single bond. In another example, the metallic radius of rhenium is 137.5 pm, with a Re–Re bond length of 224 pm in the compound Re2Cl8. From this data, we can conclude that the bond is a very strong bond or a quadruple bond. This method of determination is most useful for covalently bonded compounds. Factors affecting ionic bond energy The electronegativity of the two atoms bonding together affects ionic bond energy. Greater differences in electronegativity correspond to stronger ionic bonds. See also Binding energy Ionization energy Isodesmic reaction Lattice energy References Energy Binding energy