  We have investigated possible spin and charge ordered states in 3d
transition-metal oxides with small or negative charge-transfer energy, which
can be regarded as self-doped Mott insulators, using Hartree-Fock calculations
on d-p-type lattice models. It was found that an antiferromagnetic state with
charge ordering in oxygen 2p orbitals is favored for relatively large
charge-transfer energy and may be relevant for PrNiO$_3$ and NdNiO$_3$. On the
other hand, an antiferromagnetic state with charge ordering in transition-metal
3$d$ orbitals tends to be stable for highly negative charge-transfer energy and
can be stabilized by the breathing-type lattice distortion; this is probably
realized in YNiO$_3$.
