title: Crystalline and liquid structure of zinc chloride trihydrate: a unique ionic liquid.
abstract: The water/ZnCl(2) phase diagram in the vicinity of the 75 mol % water composition is reported, demonstrating the existence of a congruently melting phase. Single crystals of this 3-equiv hydrate were grown, and the crystal structure of [Zn(OH(2))(6)][ZnCl(4)] was determined. Synchrotron X-ray and neutron diffraction and IR and Raman spectroscopy along with reverse Monte Carlo modeling demonstrate that a CsCl-type packing of the molecular ions persists into the liquid state. Consistent with the crystalline and liquid structural data, IR spectroscopy demonstrates that the O-H bonds of coordinated water do not exhibit strong intermolecular hydrogen ion bonding but are significantly weakened because of the water's coordination to Lewis acidic zinc ions. The O-H bond weakening makes this system a very strong hydrogen-bond donor, whereas the ionic packing along with the nonpolar geometry of the molecular ions makes this system a novel nonpolar, hydrogen-bonding, ionic liquid solvent.
authors.affiliation: Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Wilcox
authors.forename: Bradley P
authors.initials: BP
authors.lastname: Losey
authors.forename: Jacob C W
authors.initials: JC
authors.lastname: Folmer
authors.forename: James D
authors.initials: JD
authors.lastname: Martin
authors.forename: Matthias
authors.initials: M
authors.lastname: Zeller
authors.forename: Roger
authors.initials: R
authors.lastname: Sommer