The composition and architecture of hydrated hydroxy anions as observed in the crystalline state – A review

Search of the Cambridge Structural Database reveals that hydrated hydroxide anions can be quite complex in their stereochemistry. As in the case of hydronium cations [I. Bernal. C.R. Chim. 9 (2006) 1454], they can be acyclic as well as cyclic. Moreover, it is documented here that hydrated hydroxide anions exist in the form of geometrical isomers or conformers. A simple example occurs in species of composition H5O3− which exist in isomeric forms in which their stereochemistry depends on whether the OH− is the hydrogen donor to waters or vice versa. All illustrations in this survey were generated with DIAMOND.