Pauling’s Rules: Guide to Coordinating Polyhedra

Linus Pauling was an American chemist who won two Nobel Prizes. He developed rules to understand the properties and structures of coordination polyhedra. Pauling’s Rules are used to determine the maximum amount of cation-to cation separation for coordination polyhedra that share vertices or edges. The sum of the anion and cation radii of (a), cubic, (b), octahedral and (c) trihedral coordination is used to calculate this (Thompson 2017,). Pauling’s Rules assume that the anions and cations in a coordination polyhedron should be as close together as possible. The electrostatic attraction forces that hold the cations together in coordination polyhedrons are stronger the closer they are. Pauling’s Rules states that the highest cation-to cation separation can be calculated by adding together the anion and cation radii and subtracting the total (R; Thompson, 2017).