  Coulomb law is one of the fundamental laws in Physics. It describes the
magnitude of the electrostatic force between two electric charges.
Counterintuitively the repulsion force between two equal electric charges in a
vacuum, stated by the Coulomb law, turn into the attraction force between the
same electric charges when they are placed next to a material with negative
permittivity and the distance between them is larger than some critical
distance. As a result the equally charged particles "crystallize" occupying
equilibrium positions. We prove this claim with the method of images for two
charged particles placed next to a material with negative permittivity.
