Determination of oxidation state of iron in garnets by Mossbauer spectroscopy
EMSL Project ID
47781
Abstract
The garnet structure is a promising nuclear waste form due to its potential of accommodating various actinide elements. Study of tetravalent cation substitution in a simple garnet system may shed light on the substitution mechanisms and their energetics. Initial experimental studies have chosen yttrium iron garnet, YIG, Y3Fe5O12 as a starting composition, and Ce4+ substitution as an analogy of Ac4+ substitution in this project. Formation of the single phase indicates that a charge coupled substitution reaction involving Fe3+/Fe2+ facilitates the incorporation of tetravalent cerium cations. However, the oxidation state of iron and cerium in the system are not well studied. Quantifying Fe2+/?Fe in the substitution system by Mossbauer spectroscopy can help us indirectly estimate Ce4+/?Ce and further test the substitution hypothesis. Also the oxidation state of cations obtained by Mossbauer spectroscopy is crucial for the interpretation of the calorimetric measurements.
Project Details
Project type
Limited Scope
Start Date
2013-02-04
End Date
2013-04-06
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Guo X, AH Tavakoli, S Sutton, RK Kukkadapu, L Qi, A Lanzirotti, M Newville, MD Asta, and A Navrotsky. 2014. "Cerium Substitution in Yttrium Iron Garnet: Valence State, Structure, and Energetics." Chemistry of Materials 26(2):1133-1143. doi:10.1021/cm403444f
Guo X., R.K. Kukkadapu, A. Lanzirotti, M. Newville, M.H. Engelhard, S.R. Sutton, and A. Navrotsky. 2015. "Charge-coupled Substituted Garnets (Y3-xCa0.5xM0.5x)Fe5O12 (M = Ce, Th): Structure and Stability as Crystalline Nuclear Waste Forms." Inorganic Chemistry 54, no. 8:4156-4166. PNNL-SA-108186. doi:10.1021/acs.inorgchem.5b00444
Long G.J., F. Grandjean, X. Guo, A. Navrotsky, and R.K. Kukkadapu. 2016. "Mössbauer Spectral Properties of Yttrium Iron Garnet, Y3Fe5O12, and its Isovalent and Nonisovalent Yttrium-Substituted Solid Solutions." Inorganic Chemistry 55, no. 7:3413–3418. PNNL-SA-114618. doi:10.1021/acs.inorgchem.5b02769