. SCSD analysis of the anthracene core of CCDC: CICWEQ, the B1u principal deformation from formation of an anthracene-9,10-endoperoxide is largest. The inclusion of both of these motifs -i.e. a sterically hindered anthracene endoperoxide, showed both of these motifs simultaneously. (Au:1.52 Å, B1u:7.12 Å, WUHTUO) (Fig. ). Au deformation is similar to other crowded anthracenes, and B1u deformation is approximately equal to that for the model anthracene-9,10-endoperoxide. This demonstrates the power of a simple additive process that is remarkably accurate at predicting dissymmetric deformations, and therefore measured atom positions.