  The Hartree-Fock (HF) method, supplemented by low-order Moller-Plesset (MP2)
perturbation theory, has been utilized to predict the nuclear geometry,
assuming planarity, of a low-lying isomer of the free space cluster BOSi$_2$.
The planar structure found at equilibrium geometry is shown to be stable
against small amplitude molecular vibrations. Finally, some brief comments are
made on the possible relevance of the above free-space cluster geometry to the
known B-O defects which limit the improvement of minority carrier lifetime in a
form of p-type silicon.
