The phase equilibria of the La2O3-SrO-CaO-Mn3O4 system in air at 1200 degre
es C has been studied. Under these conditions, eight univariant four-phase
equilbria were observed. Quaternary phases, as well as liquid phases, were
not observed. Perovskite-structure phases LaMnO3, SrMnO3, and CaMnO3 did no
t form complete solid solutions within the system.