The hydration structure of Br- from anomalous x-ray diffraction

The method of anomalous x-ray diffraction (AXD) was applied to an aqueous solution of 6 molal RbBr in water Data were gathered at two wavelengths below the absorption edge of Br-. Corrections were made for attenuation, inelastic scattering and background and container scattering. The corrected data were renormalized and put on an absolute scale of electron units. Fourier transformation of these results provided information on the Br- hydration. It is found that the Br-O nearest neighbour distance is 3.4 Angstrom and the first coordination shell contains between 6 and 7.5 water molecules. There is no evidence to suggest any longer range hydration structure.