When a cation comes very close to an anion , the nucleus of the cation, that is, the total positive charge, attracts the electron cloud of the anion to itself. At the same time cation repels the nucleus of anion. As a result of this attraction and repulsion, the electrons of the anion move towards the cloud cation. This is called cation deformation of the anion or pellarion and the anion is said to be pellarized. The ability to calibrate anion in this way is called calibrating power of cation.