33. 4 Some Rules Governing the Ionic Compounds Pauling's three rules governing the structure of ionic compounds 1. Anion Coordination polyhedron rule Each cation is surrounded by an anion polyhedron, the distance between anion and cation is r=rt tr, while the CN depends on rt§3.4 Some Rules Governing the Ionic Compounds Pauling’s three rules governing the structure of ionic compounds. 1. Anion Coordination polyhedron rule Each cation is surrounded by an anion polyhedron, the distance between anion and cation is ro ＝r +＋r - , while the CN depends on r +/r-