The fact that there are Mn2+ at the A sites in the ABO3 perovskite phase of manganites with the nominal composition La0.6-xNdxSr0.1MnO3 showed by detailed experimental study and theoretical calculations.The magnetic moments of these Mn2+ are antiparallel to those of the Mn ions at the B sites.The content of the Mn2+ increases as the average ionic radius,(rA),of the ions at A sites decreases,resulting in the experimentally observed phenomenon that the content of the Mn3O4 phase in the manganites decreases with decreasing 〈rA〉.