The o-factors of the 2] and 4] states in 198,2oo, 2O2Hg were simultaneously measured by means of the transient-field perturbed angular correlation method in Coulomb excitation using multi-isotopic targets and thin polarized Gd foils as ferromagnetic host. The g(2[) and 9(4 ~) were found identical within errors in ~ 98,2OOHg ' while in 2~176 lower o-factor values have been determined. The experimental 0-factors were compared with the predictions of the pairing-plus-quadrupole, dynamical deformation and interacting boson models.