In a theoretical study of a "defect perovskite" structure of stoichiometry AeTiO(2) (AE alkaline earth metal, Be, Mg, Ca, Sr, and Ba), we find substantial Ti-Ti bonding tuned by the size of the Ae(2+) cation. The bonding is one-dimensional, partially a, partially H. These formal d(2) systems are expected to be nonmagnetic and metallic. A competing (for same Ae) structural alternative, an ordered rock-salt structure, is magnetic.