The series of cations N2X+((X) over tilde (1)Sigma(+)), with X = F, Cl, Br, I, has been theoretically studied by variational multireference CI and coupled-cluster techniques in conjunction with basis sets of quintuple-zeta quality. We report electronic and geometric structure data and harmonic frequencies as well as binding energies and potential energy curves. A new rationalization is provided for the bonding mode in N2F+, which provides an explanation for the unusually short N-F bond.