Changes in the valency and coordination states of iron in FeAlPO-5 and FeAlPO-11 during reduction-oxidation treatments were followed by extracting isomer shift, quadrupole splitting and relative absorption area data from in situ Mössbauer spectra. Facile Fe3+ → Fe2+ reduction was detected, and the Fe2+ formed was stabilized in a low symmetry coordination state. The bonding strength, characterized by the Debye temperature (ΘD), was considerably smaller for Fe2+ than for Fe3+ (ΘD(Fe2+) = 170 K, ΘD(Fe3+) ≈ 500 K).
ASJC Scopus subject areas
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films
- Materials Chemistry