A theoretical study of the lithium fluoride molecule in water

Abstract

Monte Carlo results are reported for the structure of molecular clusters consisting of a lithium fluoride ion pair surrounded by 50 water molecules at temperatures of 298 and 500 K using Hartree-Fock interaction potentials that include some three-body terms. It is shown that when separated by distances of between 3 and 4 Å each ion is surrounded by a nearest-neighbor shell of four atoms, hydrogen in the case of the fluoride ion and oxygen in the case of the lithium ion. There is evidence of both secondary hydrogen atom and secondary oxygen atom structure around the ions but there is no evidence of any larger hydration shell. It is tentatively concluded that the coordination number of 4 for each ion is responsible for the behavior of lithium and fluoride ions as "structure makers." Copyright © 1974 American Institute of Physics.