  The Bohr-Mottelson model is solved for a generic soft triaxial nucleus,
separating the Bohr hamiltonian exactly and using a number of different
model-potentials: a displaced harmonic oscillator in $\gamma$, which is solved
with an approximated algebraic technique, and Coulomb/Kratzer,
harmonic/Davidson and infinite square well potentials in $\beta$, which are
solved exactly. In each case we derive analytic expressions for the
eigenenergies which are then used to calculate energy spectra.
  Here we study the chain of osmium isotopes and we compare our results with
experimental information and previous calculations.
