  Sc and Mn abundances are determined for 119 F and G main-sequence stars with
-1.4 < [Fe/H] < +0.1, representing stars from the thin disk, the thick disk and
the halo. The results indicate that Sc behaves like an alpha-element, showing a
decreasing [Sc/Fe] with increasing metallicity in disk stars and a dual pattern
in the kinematically selected halo stars. In contrast, Mn shows an increase
from [Mn/Fe] = -0.5 at [Fe/H] = -1.4 to zero at solar metallicity. There
appears to be a discontinuity or sharp increase of [Mn/Fe] at [Fe/H] = -0.7
corresponding to the transition between the thick and the thin disk. It is
discussed if supernovae of Type Ia are a major source of Mn in the Galactic
disk or if the trend of [Mn/Fe] vs. [Fe/H] can be explained by nucleosynthesis
in Type II supernovae with a strong metallicity dependence of the yield.
