Formation of Oxide Phases in the System Pr-Fe-O

The formation of oxide phases at 900°C in the system [Fe.sub.2][O.sub.3]-"[Pr.sub.2][O.sub.3]" was investigated. With a decrease in the molar fraction of [Fe.sub.2][O.sub.3] a corresponding increase in PrFe[O.sub.3] was observed. For equal molar fractions of [Fe.sub.2][O.sub.3] and "[Pr.sub.2][O.sub.3]" the formation of PrFe[O.sub.3] and very small fractions of α-[Fe.sub.2][O.sub.3] plus an additional oxide phase, which could not be identified with certainty, were observed. With further increase in "[Pr.sub.2][O.sub.3]" fraction the praseodymium oxides [Pr.sub.6][O.sub.11] and Pr[O.sub.2] started to become dominant in the phase composition. The small fraction (< 0.02) of the same unidentified oxide phase was also obtained when Pr[(OH).sub.3] was calcined in air at 900°C; this was probably a mixture of other praseodymium oxides with different average oxidation numbers of Pr. The results of XRD, [sup.57]Fe Mossbauer and FT-IR spectroscopies are discussed. (doi: 10.5562/cca2247) Keywords: α-[Fe.sub.2][O.sub.3], PrFe[O.sub.3], praseodymium oxides