  Vortex phase in a singlet superconductor in the absence of impurities is
shown to be absolutely unstable with respect to the appearance of a triplet
component which breaks both inversion and time-reversal symmetries of Cooper
pairs. Symmetry breaking paramagnetic effects are demonstrated to be of the
order of unity if the orbital upper critical field, Hc2(0), is of the order of
Clogston paramagnetic limiting field, Hp. We suggest a generic phase diagram of
such type-IV superconductor, which is singlet one at H=0 and characterized by
mixed singlet-triplet order parameter with broken time-reversal symmetry in
vortex phase. A possibility to observe type-IV superconductivity in clean
organic, high-Tc, MgB2, and other superconductors is discussed.
