# Atom instead of ion size

I have noticed that when you import crystal data for a ionic compound - for instance, KCl - you get the size of the atoms instead that of the ions. I would expect 1,52 A for K+ and 1,67 A for Cl-, but you get 1,96 for K and 0,99 for Cl. Is that because the force field function works for atoms and not for ions? Besides the fact that you get a wrong image of the crystal structure, is the value of energy correct?
Thanks for your answer
Eugenio