Modelling disorder in 3,3′-dimethoxybenzil, C₁₆H ₁₄O₄

This work is part of an extended study of benzil (C₁₄H ₁₀O₂) and some of its derivatives which aims to understand the role of molecular flexibility in crystal packing and polymorphism. Significant steps have been made in modelling the structured thermal diffuse scattering from 3,3′-dimethoxybenzil, C₁₆H₁₄O ₄. It appears that the structure can be considered as a stack of layers of molecules in which interactions are strongest within the layers. The layers interact weakly along the a direction but more strongly along c, so shearing of the planes relative to each other is energetically likely. The molecule must be treated as flexible for a good model to be found.