, where
ION BOND
Ion bond is the interacting force between ions. The energy of the interaction of two ions and charges q1 and q2 is inversely proportional to the distance r between them and it is equal to
, where
ε - is electric permittivity of the medium,
ε0 - is electric permittivity of vacuum.
Similar charges repel and U > 0, unsimilar charges gravitate and U < 0.