Analysis of the structure and morphology of fenoxycarb crystals

• Two distinct modes of molecular interactions govern the growth of the FC crystal.
• A facile method is proposed to estimate these interactions at the DFT level.
• We predict and observe that the crystal morphology is dominated by the {0 0 1} faces.
• The aromatic and aliphatic terminated {0 0 1} faces have similar, high stability.
• The {0 0 1} faces should favour neither aliphatic nor aromatic termination.

In this paper, we have explored the relationship between surface structure and crystal growth and morphology of fenoxycarb (FC). Experimental vs. predicted morphologies/face indices of fenoxycarb crystals are presented. Atomic-scale surface structures of the crystalline particles, derived from experimentally indexed single crystals, are also modelled. Single crystals of fenoxycarb exhibit a platelet-like morphology which closely matches predicted morphologies. The solvent choice does not significantly influence either morphology or crystal habit. The crystal morphology is dominated by the {0 0 1} faces, featuring weakly interacting aliphatic or aromatic groups at their surfaces. Two distinct modes of interaction of a FC molecule in the crystal can be observed, which appear to be principal factors governing the microscopic shape of the crystal: the relatively strong collateral and the much weaker perpendicular bonding. Both forcefield-based and quantum-chemical calculations predict that the aromatic and aliphatic terminated {0 0 1} faces have comparably high stability as a consequence of weak intermolecular bonding. Thus we predict that the most developed {0 0 1} surfaces of fenoxycarb crystals should be terminated randomly, favouring neither aliphatic nor aromatic termination.

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