Crystal symmetries structure predictions

X-ray studies also indicate that the same type of structure may be assigned to the basic propionate, triacetate tripropionate, isobutyrate, butyrate, and pivalate. It may therefore be assumed as general for all members of the series. In the basic formate and acetate, complete crystal symmetry is predicted by structures of this type. Replacement of the hydrogen or methyl with radicals such as ethyl and propyl should induce dissymmetry. That this is true is shown by the crystal habits of these compounds. The basic acetate crystallizes in the cubic system, but the basic propionate, triacetate tripropionate, and pivalate are monoclinic in form, and the basic isobutyrate crystallizes in the triclinic system. The low melting point of the basic butyrate made a complete x-ray investigation difficult, but the crystals were shown to be of very low symmetry. ... 

The crystallization of achiral molecules in chiral space groups, while rare and unpredictable, is well documented. Molecules with a C2 symmetry axis tend to crystallize in chiral structures, according to Jacques and coworkers, but despite impressive work on crystal engineering, predictions of a correlation between crystal symmetry and molecular structures are still hard to make [6]. 

C. Powder Indexing completes a comprehensive package of software modules for crystal structure determination from powder data. It is possible to establish unit cell and symmetry information, and use this to assist Rietveld refinement or crystal structure predictions. 

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