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In page Linus Pauling:

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In 1929, Pauling published five rules which help to predict and explain crystal structures of ionic compounds.[1][2] These rules concern (1) the ratio of cation radius to anion radius, (2) the electrostatic bond strength, (3) the sharing of polyhedron corners, edges and faces, (4) crystals containing different cations, and (5) the rule of parsimony.[citation needed]