The equilibrium structure and molecular properties of trans-1-chloro-2-fluoroethylene have been investigated theoretically at high level of theory. Very accurate results are presented. As far as the equilibrium structure is concerned, coupled-cluster approach with perturbative inclusion of triples and basis sets of triple and quadruple zeta quality have been employed. Core correlation effects and basis set limit extrapolation have been taken into account in order to obtain best estimates of equilibrium geometry. The molecular dipole moment has been calculated at coupled-cluster level using bases of different quality including diffuse functions and performing the extrapolation to the infinite basis set limit. In addition, the complete inertial nuclear quadrupole tensor, evaluated from the electric field gradient at the chlorine nucleus, has been computed at different level of theory: The multiconfiguration self-consistent field, the Moller-Plesset many-body perturbation to second order and the coupled-cluster methods have been employed. Finally, the harmonic force field has been calculated by means of coupled-cluster approach with a basis of triple zeta quality. (C) 2003 American Institute of Physics.