  Formation energy of the \sigma-phase in the Fe-V alloy system, \Delta E, was
computed in the full compositional range of its occurrence (34 < x < 60) using
the electronic band structure calculations by means of the KKR method. \Delta
E-values were found to strongly depend on the Fe concentration, also its
variation with different site occupancies was characteristic of a given lattice
site. Calculated magnetic and configuration entropy contributions were used to
determine sublattice occupancies for various compositions and temperatures. The
results agree well with those obtained from neutron diffraction measurements.
