Bond Paths and van der Waals Interactions in Orpiment, As2S3

The calculated electron density distribution for orpiment, As2S3, reveals that As-S, S-S, and As-As bond paths are associated with the experimental interlayer directed bonded interactions detected in a combined infrared and Raman study. The successful modeling of the infrared- and Raman-determined interlayer bonded interactions together with bond paths and the structuralization of a variety of inorganic molecules in terms of key-lock bond path mainstays support the argument that van der Waals forces in inorganic molecular crystals are directional.