  It is shown that for the theoretical description of the magnetic and
structural phase transitions in the magnetics with magnetoactive ions of
transition metals within the framework of the Landau theory of phase
transitions the exchange group GxO(3) should be chosen as the group of symmetry
of paramagnetic phase. Such a choice allows to describe the transition from the
paramagnetic phase into the isotropic magnetically ordered phase (at Tc), and
the spin-orbit transition from the isotropic into the anisotropic phase (at
T<Tc). The exchange multiplet describes the spin-orbit phase transition.
