Thermodynamics of the Eu(<scp>iii</scp>)–Mg–SO<sub>4</sub>–H<sub>2</sub>O and Eu(<scp>iii</scp>)–Na–SO<sub>4</sub>–H<sub>2</sub>O systems. Part II: spectroscopy experiments, complexation and Pitzer/SIT models
Dalton transactions