We use first-principles calculations to investigate the electronic structur
e, atomic geometries and formation energies of point vacancies (V-B, V-N),
antisites (B-N, N-B) and interstitials (B-i, N-i) in cubic boron nitride (c
-BN). We find that nitrogen and boron vacancies exhibit the lowest formatio
n energies in nonstoichiometric c-BN for p-type and n-type conditions, resp
ectively, showing intrinsic donor (V-B) and acceptor (V-N) characters. The
equilibrium geometries show large outward breathing relaxations for both va
cancies and for B-N, With Slight Jahn-Teller distortions from T-d symmetry.
For N-B we find an off-center distortion inducing a negative-U behavior in
this center. For both interstitial centers we find stable configurations i
n which an atomic pair occupies a nitrogen site in the lattice, N-N for Ni
and N-B for B-i. These systems are stable for the different charge states i
nvestigated.