Three different published tests concerning twinning by merohedry were applied to single-crystal data sets for 5 different inorganic crystal structures. Although the 3 test procedures differed significantly with regard to their efficiency in detecting the existence of twinning and in estimating the volume fractions of the twin individuals, they were considered to be useful tools in the early stages of structure analysis and should be applied during the early stages of structure determination whenever twinning by merohedry was possible.

Application and Comparison of Different Tests on Twinning by Merohedry. V.Kahlenberg: Acta Crystallographica B, 1999, 55[5], 745-51