The hydrogen-bond network in sodium chloride tridecahydrate: analogy with ice VI

The structure of a recently found hyperhydrated form of sodium chloride (NaCl · 13H2O and NaCl · 13D2O) has been determined by in situ single-crystal neutron diffraction at 1.7   GPa and 298   K. It has large hydrogen-bond networks and some water molecules have distorted bonding features such as bifurcated hydrogen bonds and five-coordinated water molecules. The hydrogen-bond network has similarities to ice VI in terms of network topology and disordered hydrogen bonds. Assuming the equivalence of network components connected by pseudo-symmetries, the overall network structure of this hydrate can be expressed by breaking it down into smaller structural units which correspond to the ice VI network structure. This hydrogen-bond network contains orientational disorder of water molecules in contrast to the known salt hydrates. An example is presented here for further insights into a hydrogen-bond network containing ionic species.
Source: Acta Crystallographica Section B - Category: Chemistry Authors: Tags: salt hydrate hydrogen bonds high pressure single-crystal neutron diffraction research papers Source Type: research