Example Polymorph Prediction for Estrone

As an illustration of the procedure given above, we will describe a prediction of possible polymorphs for the steroid estrone. The structures of three polymorphs of estrone are available in the one structure in space group 

we build models of the molecule we will use in our prediction. The molecule is sketched and optimized using a suitable force field. A search in the CSD for steroids with an identical ring skeleton will reveal that this type of skeleton is rather rigid because of the aromaticity of the first ring. The skeleton of our optimized molecule should fit reasonably well onto those of the experimental structures. Although the skeleton is rigid, there is some conformational 

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