Martynov Batsanov EN Mulliken EN Allred EN Nagle EN Putz, Russo, Sicilia EN Gordy EN Ghosh EN Atomic radius calculated self-consistent field method calculation Any size scale is the most helpful property for crystal structure classification. (Similar to Pauling's radius ratio rule.) Covalent radius single bond distance as a sum of covalent radii Ionic radius monoatomic ion size in ionic crystal Effective ionic radius revised ionic radius Miracle radius radii from binary metallic glasses van der Waals radius from mechanical properties of gasses property origin