Correlation studies in organic solids

Structure correlation studies were first carried out on intramolecular parameters, a classic work of which involved molecular deformations at a carbonyl center as a function of the intermolecular distance to an incoming nucleophile. In further applications, the term ‘structure correlation’ was extended to include all studies in which molecular or crystal properties are analysed in a systematic way over the database, to reveal correlations between structural or energetic properties of crystallised molecules. This chapter discusses correlation studies in organic solids, the Cambridge Structural Database (CSD) of organic crystals, structure correlation, retrieval of crystal and molecular structures from the CSD, the SubHeat database, geometrical categorisation of intermolecular bonding, space analysis of molecular packing modes, empty space versus filled space, close packing in crystals, calculation of intermolecular energies in crystals, basic concepts on lattice energies, sublimation entropies and vapor pressures of crystals, general-purpose force fields for organic crystals, correlation between molecular and crystal properties, and acceptable crystal structures.