A　series　of　oxides　in　the　Mn3O4-Fe2O3　system　have　been　synthesized　at　1200　degrees　C　in　air,　followed　by　quenching　to　room　temperature.　Three　solid　solutions,　Mn3-3xFe3xO4　(0.00　＜=　x　＜=　0.278),　Mn3-3xFe3xO4(0.291　＜=　x　＜=　0.667),　and　Mn2-2xFe2xO3　(0.89　＜=　x　＜=　1.00),　have　been　identified　by　powder　X-ray　diffraction　(XRD).　Rietveld　refinement　of　the　XRD　data　show　that　the　solids　belong　to　the　hausnnannite　phase　with　the　space　group　l4(1)/amd,　the　spinel　phase　with　the　space　group　Fd3m,　and　the　hematite　phase　with　the　space　group　respectively.　Between　these　are　two-phase　regions.　Fe-57　Mossbauer　spectra　indicate　that　the　valence　state　of　Fe　in　the　three　solid　solutions　is　+3;　in　addition,　there　are　two　crystallographically　independent　Fe3+　ions　in　the　unit　cells　of　the　hausmannite　and　spinel　phases,　and　one　Fe3+　in　the　hematite　phase.　Analyses　of　Fe-57　Mossbauer　spectra　and　X-ray　photoelectron　spectra　(XPS)　revealed　that　a　formula　of　Mn1-x2+Fex3+[Mnx2+Fex3+Mn2-3x3+]　O-4　describes　the　cation　distribution　of　both　the　hausmannite　and　spinel　phases,　but　that　for　the　hematite　phase　is　Mn2-2x3+Fe2x3+O3.