  The temperature dependence of resistivity, magnetization and electron-spin
resonance of the $\alpha- MnS $ single crystal were measured in temperature
range of $5 K < T < 550 K$. Magnetization hysteresis in applied magnetic field
up to 0.7 T at $T=5 K, 77 K, 300 K$, irreversible temperature behavior of
magnetization and resistivity were found . The obtained data were explained in
terms of degenerate tight binding model using random phase approximation. The
contribution of holes in $t_{2g}$ and $e_g$ bands of manganese ions to the
conductivity, optical absorbtion spectra and charge instability in $\alpha -MnS
$ were studied. Charge susceptibility maxima resulted from the competition of
the on-site Coulomb interaction between the holes in different orbitals and
small hybridization of sub-bands were calculated at $T=160 K, 250 K, 475 K$.
