What is the difference between crystal radius and ionic radius? For $\ce{NaCl}$ for example the ions combine to a crystal, and I would have guessed they are equal. But I then found an example of data, where they are not.

I am aware that ionic radius is the radius of an atom's ion. Quite simple. So what is crystal radius?

• I have found two different uses of the term "Crystal Radius." First is Linus Pauling's use of Crystal Radaii, which refers to ions that are free and not part of a crystal. The second is used to describe some parameters of the flame fusion crystal growth this paper, which would seem to be very much incorporated into the crystalling structure. This seems to be a rarely encountered term. Where did you encounter it? – Dale May 30 '15 at 23:55
• Similar question: researchgate.net/post/… – Dale May 30 '15 at 23:57
• There is a table of "Pauling Empirical Crystal Radiuses", which cites the following sources: Galasso, Francis S. Structure and Properties of Inorganic Solids. Oxford: Pergamon Press, 1970. Pauling, Linus. The Nature of the Chemical Bond, 3rd edition. Ithaca, NY: Cornell University Press, 1960. Rohrer, Gregory S. Structure and Bonding in Crystalline Materials. Cambridge: Cambridge University Press, 2001. – Dale May 31 '15 at 3:06

Shannon published simultaneously two sets of ionic radii. So called "effective ionic radii" were made consistent with Pauling's r($\mathrm{O_2^-}$)=140 pm. "Crystal radii" are using Shannon's value r($\mathrm{O_2^-}$)=126 pm.