In order to describe the zinc--water interaction correctly, a new ab initio potential was developed consisting of pair interaction terms as well as three-body contributions. Within this approach, it was possible to correct for the well-known failures of pair potentials in describing solvation phenomena of such ions. A first-shell coordination number of 6 in agreement with experimental data was obtained from Monte Carlo simulations of a single zinc(II) ion in water. The structure of the hydrated ion is discussed in terms of radial density functions and coordination number, energy, and angular distributions.