X-Ray Diffraction Studies of Aqueous Alkaline-Earth Chloride Solutions

Electron radial distribution functions derived from x‐ray diffraction measurements are presented for six concentrated aqueous alkaline‐earth chloride solutions. Analysis of these functions indicates that magnesium, calcium, strontium, and barium ions are hydrated by 6.5–8.0 water molecules in concentrated chloride solutions. Magnesium ions significantly alter and order the water structure; calcium ions more markedly so as evidenced by significant second‐nearest‐neighbor coordinations. The hydration of magnesium and calcium ions appears to be independent of the concentrations of ions in solution from $N_{{\mathrm{MgCl}}_2}\text{=0.071}$ and $N_{{\mathrm{CaCl}}_2}\text{=0.055}$ to saturation.