Definitive crystal structures of ortho-, meta- and para-carboranes: Supramolecular structures directed solely by C-H center dot center dot center dot O hydrogen bonding to hmpa (hmpa equals hexamethylphosphoramide)

Cocrystallisation of ortho- meta- and para-carboranes with hmpa (hexamethylphosphoramide) results in the isolation of 1:1 carborane,hmpa adducts which provide the first definitive X-ray structures of the unsubstituted carboranes as part of three very different C-H...O hydrogen-bonded supramolecular structures.