Overlooked Solid State Structure of 1,3-I₂C₆F₄-The Meta-Member of an Iconic Halogen Bond Donors Trio

The solid-state structure of the meta-isomer of diiodotetrafluorobenzene (DITFB), the sole liquid DITFB at 25 degrees C, is reported. Computational and comparative analyses of its crystal packing have elucidated potential factors contributing to its lower melting point and reduced affinity as a halogen bond donor conformer as compared to the para-isomer. This discussion also addresses the lower melting points of ortho- and meta-isomers in general. The platelet crystal habit of 1,3-DITFB is examined in relation to its energy framework pattern, proposing a comprehensive and illustrative predictive model for its faster growth in the [001] direction. This growth aligns with the maximum attachment energy.