Iron-57 Mössbauer spectroscopy study of phases in the CaZrTi2−2 x Nb x Fe x O7 zirconolite system.

Materials of composition CaZrTi2−2 x Nb x Fe x O7 with the fluorite-related zirconolite structure have been prepared. The 57Fe Mössbauer spectra show that iron is initially located in the five co-ordinate cation sites. As the iron content increases the iron enters the octahedral sites until, at a composition CaZrTi0.4Nb0.8Fe0.8O7, ca. 50% of the iron is five co-ordinate and the remainder is located in the octahedral sites. [ABSTRACT FROM AUTHOR]