Solid-state modeling, application crystallization

The crystal properties can be related to the intermolecular forces between molecules, and hence the application of solid state modeling techniques are playing an increasingly important role as a tool to aid in the visualization and explanation of complex crystallization phenomena. 

This paper will focus on the application of solid state modeling techniques to one particular particle property - crystal habit. A morphological study on the analgesic aspirin (C9H8O4) will be presented in order to assess the effects of morphology on processing, and materials handling. The crystal chemistry will be... 

Single crystal X-ray structure analyses of analogously substituted adducts confirmed the applicability of this model. Adducts of the type EtaAl—E(Tms)3 and f-BuaAl—E(i-Pr)3 (E = P, As, Sb, Bi) were structurally characterized [50], allowing detailed comparisons of their solid state structural parameters. The trends observed for the average Al—C bond lengths and the C— Al—C bond angular sums are summarized in Figs. 5 and 6. 

Seiler and Dunitz point out that the main reason for the widespread acceptance of the simple ionic model in chemistry and solid-state physics is its ease of application and its remarkable success in calculating cohesive energies of many types of crystals (see chapter 9). They conclude that the fact that it is easier to calculate many properties of solids with integral charges than with atomic charge distributions makes the ionic model more convenient, but it does not necessarily make it correct. 

GP Stahly, SR Byrn. The solid-state structure of chiral organic pharmaceuticals. In AS Myerson, ed. Molecular Modeling Applications in Crystallization. Cambridge, U.K. Cambridge University Press, 1999, chap. 6. 

Many types of energy calculations have been applied in CSP studies, starting from the simplest atom-atom descriptions of interactions. While fairly simple brute force (grid and random strncture generation) approaches are often suc-cessfnl at addressing the crystal structure generation problem, the assessment of relative energies requires the development of sophisticated methods to achieve the required accuracy for CSP. One approach has been the development of more elaborate, anisotropic (nonspherical) atom-atom models." Recently, the application of QM solid-state electronic strncture calculations has also been demonstrated to be very successful. " ... 

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