Z(5): critical point symmetry for the prolate to oblate nuclear shape phase transition

A critical point symmetry for the prolate to oblate shape phase transition is introduced, starting from the Bohr Hamiltonian and approximately separating variables for γ=30 deg. Parameter-free (up to overall scale factors) predictions for spectra and B(E2) transition rates are found to be in good agreement with experimental data for 194Pt, which is supposed to be located very close to the prolate to oblate critical point, as well as for its neighbours (192Pt, 196Pt)