[phenixbb] ionic radius

Greetings, I was wondering if someone can enlighten me on the issue of how the metal ionic radius are defined in the protein structures. Is there any place in the refinement process where we can define it or it is automatically taken from some library in the phenix background. What is a good resource for knowing the ionic radii, I came across this one in an old blog post http://abulafia.mt.ic.ac.uk/shannon/ is there any other source that is used. Thanks so much in advance Manoj Saxena