We report results from a theoretical study on the solvation of the divalent cations of Mg, Ca and Sr in water at infinite dilution. The ions are treated at the Hartree-Fock level with an explicit solvent model. Electrostatics, polarization and exchange repulsion contribute to the Hamiltonian. The dominating coordination number for the ions increases from 6 for Mg through 7 for Ca to 8 for Sr. A broadening of the first peak in the radial distribution function is seen when going down the periodic system. (c) 2006 Elsevier B.V. All rights reserved.