Textbook structure rules formulated by Linus Pauling 90 years ago prove unreliable

Rules devised by double Nobel prize winner Linus Pauling describing the preferred crystal structures ionic compounds adopt are more like loose guidelines, chemists in Belgium have discovered. Janine George, Geoffroy Hautier and colleagues at the Catholic University of Louvain tested the five rules against 5000 oxide structures. They found that just 13% satisfied four of the five rules, a fact Hautier describes as ‘shocking’. ‘These rules, despite being taught in every chemistry textbook, have a much lower predictive power than one would think,’ he says.