Cimetidine, C₁₀H₁₆N₆S, form C: crystal structure and modelling of polytypes using the superspace approach

An efficient method for modelling a polytypic family is presented with the example of cimetidine in the form C polymorph. The method exploits the (3 + 1)-dimensional superspace model, which is a powerful tool for the description, prediction and understanding of polytype modifications in small-molecule crystallography, as illustrated with this pharmaceutical example.