Structural parameters of hydration of Be2+ and Mg2+ ions in aqueous solutions of their salts

Published data on structural characteristics of hydration of beryllium and magnesium ions in aqueous solutions of their salts under standard conditions, obtained by various methods, as well as authors’ X-ray data are reviewed. Structural parameters of the immediate environment of Be2+ and Mg2+, specifically coordination numbers, interparticle distances, and types of ionic association, are discussed. It is noted that Be2+ coordinates four water molecules at an average distance of 0.167 nm and Mg2+ coordinates six water molecules at an average distance of 0.210 nm. In aqueous solutions of their salts, both Be2+ and Mg2+ form the second coordination spheres.