Higher hydrates of lithium chloride, lithium bromide and lithium iodide

Abstract

For lithium halides, LiX (X = Cl, Br and I), hydrates with a water content of 1, 2, 3 and 5 moles of water per formula unit are known as phases in aqueous solid-liquid equilibria. The crystal structures of the monohydrates of LiCl and LiBr are known, but no crystal structures have been reported so far for the higher hydrates, apart from LiI·3HO. In this study, the crystal structures of the di- and trihydrates of lithium chloride, lithium bromide and lithium iodide, and the pentahydrates of lithium chloride and lithium bromide have been determined. In each hydrate, the lithium cation is coordinated octahedrally. The dihydrates crystallize in the NaCl·2HO or NaI·2HO type structure. Surprisingly, in the tri- and pentahydrates of LiCl and LiBr, one water molecule per Li ion remains uncoordinated. For LiI·3HO, the LiClO·3HO structure type was confirmed and the H-atom positions have been fixed. The hydrogen-bond networks in the various structures are discussed in detail. Contrary to the monohydrates, the structures of the higher hydrates show no disorder.

Terahertz Signatures of Hydrate Formation in Alkali Halide Solutions

“…The distinct differences between the spectra of salt tablets and the frozen solutions indicate hydrate formation. This is also consistent with the previous report, where these lithium and fluoride salts do form hydrates. These results reveal that ions Li + and F – also play substantial roles in salt hydrate formation.…”

Molten Salt Hydrates in the Synthesis of TiO2 Flakes

“…In addition to the fact that the ions of the salt are not well separated, these solutions have the ability to maintain an ordered structure of water within the salt ions. 52 We hypothesize that this ordered structure is responsible for the ordered agglomeration of small TiO 2 nanoparticles in an apparent film-like morphology. As the titanium alkoxide precursor reacts very fast with water molecules, we believe that the hydrolysis and condensation occur rapidly in the regimes of water molecules that interact only with the dissociated ions.…”

Effective Volumes of Waters of Crystallization: Ionic Systems

“…A data set of 182 unduplicated hydrate–parent pair values was extracted from the full data set generally by arbitrarily retaining only the last value in each duplicated set of values. Outlier data from the initial data set were replaced with X-ray diffraction data from the Inorganic Crystal Database, while recent data on the lithium halide hydrates and the high hydrates of the Mg, Ca, and Al halides − were added.…”