Be2Hydration in Concentrated Aqueous Solutions of BeCl2.

Neutron diffraction experiments were carried out on concentrated aqueous solutions of beryllium chloride at three concentrations:  1.5, 3, and 6 molal. By working with a specific (“null”) mixture of heavy water (D2O) and water (H2O), information on the local structure around Be2ions was extracted directly. For all three BeCl2solutions, the results show that the Be2ion has a well-defined 4-fold coordination shell that is dominated by oxygen atoms. There is also a relatively small probability (10−15%) that there are direct contacts between Be2and Cl-at a distance of ∼2.2 Å. The oxygen atoms of the highly structured Be2first hydration shell are found to be situated at 2.6 Å apart, and form a pyramidal structure, in agreement with recent MD simulation results. The Cl-ions have approximately seven oxygen atoms (water molecules) in their hydration shells sited at 3.2 Å. [ABSTRACT FROM AUTHOR]