Prediction of anion distributions using Pauling's second rule.

Pauling's second crystal rule is shown to be able to predict in a general and simple way the distribution of anions in mixed oxyanion systems such as oxynitrides and oxyhalides with diverse compositions and structure types. Results are presented in a plot correlating the charge of the anions obtained from the observed occupancies in crystallographic positions with the calculated bond strength sums for these sites.