Skip to main content Accessibility help
×
Home

Analysis of Coordination Polyhedra Symmetry in Pyrochlore and Zirconolite Structures

  • A. Y. Troole (a1) and S. V. Stefanovsky (a1)

Abstract

Zirconolite and pyrochlore are considered as promising host phases for high level waste (HLW). However, correct information on substitution mechanisms, forms of dopants incorporation in their structures and distortions in coordination polyhedra is presently unavailable. To clarify these points we use the electron paramagnetic resonance (EPR). Pyrochlore and three of zirconolite polytypes: zirconolite-2M, zirconolite-3T, and zirconolite-30 are considered. Pyrochlore is the “parent” structure for zirconolite since any zirconolite variety is produced by means of distortion of the initial pyrochlore structure. Space groups of pyrochlore and basic polymorphous zirconolite varieties found from XRD and TEM data, as well as interatomic distances and angles, were taken from reference data. This allows the determination of the most probable sites for impurities, substitution mechanisms, and local symmetry of coordination polyhedra (initial). Ions chosen for EPR were Gd (III) as an analog of trivalent rare earth and actinide elements which are also occurred in HLW and Fe (III) as a typical corrosion product which occurs in all HLW. For Gd (III) a strong ligand field approximation is suggested, theoretical computation using perturbation theory in this approximation has been carried out. All the non-diagonal members plus magnetic field were chosen as perturbation and formulae for transition frequencies, estimations of fine structure and g-factors parameters in the given approximation have been obtained.

Copyright

References

Hide All
1. Aleshin, E., Roy, R., J. Amer. Cream. Soc. 45, 18 (1962).
2. Chakoumakos, B. C., Ewing, R. C., in Sciefnlific Basis for Nuclcear Wascle Management IX edited by Jantzen, C. M., Stone, J. A. and Ewing, R. C. (Mat. Res. Soc. Symp. Proc 44, Pittsburgh, PA, 1985) pp. 641646.
3. Lumpkin, G., Ewing, E. C., Phys. Chem.Minerals 16, 2 (1988).
4. Ewing, R. C., Weber, W. J., Lutze, W., Dissposal of Weapon Plutonium, edited by Merz, E. R. and Walter, C. E. (Kluwer Academic Publishers, Amsterdam, 1996) pp. 6583.
5. Lumpkin, G. R., Ewing, R. C., Chakoumakos, B. C., Greegor, R. B, Lytle, F. W.; Foltyln, E. M, Clinard, F. W. Jr., Boatner, L. A., Abraham, M. M., J. Mater. Res. 1, 564 (1986).
6. Gatehouse, B.M., Grey, I.E., Roderick, J.H., Rossell, H.J., Acta Cryst. B 37, 306 (1981).
7. Mazzi, F., Munno, R., Amer. Mineral. 68, 262 (1983).
8. Vance, E. R., Begg, B. D., Day, R. A., Ball, C. J., in Scientific Basis for Nuclear’ Wast/Manatigemet XVIII, edited by Murakami, T. and Ewing, R. C. (Mat. Res. Sos. Symp. Proc. 353 Pittsburgh, PA, 1995), pp. 767774.
9. Vance, E. R., Jostsons, A., Day, R. A., Ball, C. J., Begg, B. D., in Scientific Bcasis for Nuclear Waste Mancagement XV7III, edited by Murphy, W. M. and Knecht, D. A. (Mat. Res. Soc. Symp. Proc. 412, Pittsburgh, PA, 1996) pp, 41–47.
10. Vance, E. R., Hart, K. P., Day, R. A., Begg, B. D., Angell, P. J., Loi, E., Weir, J., Oversby, V. M., in scientific Basis for Nuclear Waste Mtnagemente Xl'lll, edited by Murphy, W. M. and D.A, Knecht (Mat. Res. Soc. Symp. Proc. 412, Pittsburgh, PA, 1996) pp. 4955.
11. Rappaz, M., Abraham, M. M., Ramey, J. O., Boatner, L. A., Phys. Rev. B 23, 1012 (1981).
12. Troole, A. Y., Stefanovsky, S. V., Bogomolova, L. D.. Phys. Chem. Mater. Treat (Russ.) 4, 75 (1998).
13. Muller, K. A., Univerisitesforlaget, 61–96 (1971).
14. Kliava, J., EPR, Spectroscojy Disordered, Solids (Zinatne, Riga, 1988).
15. Fielding, P. E., White, T. J., J. Mat. Res. 2 (3) 387 (1987).
16. Iton, L. E., Brodbeck, C. M., Suib, S. L., Stucky, G. D., J. Chem. Phys. 79 (3) 1135 (1983).
17. Knyazev, O. A., Stefanovsky, S. V., Ioudintsev, S. V., Nikonov, B. S., Omelianenko, B. I., Mokhov, A. V., Yakushev, A. I., in Scientific Basis for Nucleair Watste Malnagemeniet XX, edited by Gray, W. J. and Triay, I. R. (Mat. Res. Soc. Symp. Proc. 465, Pittsburgh, PA, 1997) pp. 401408.
18. Knyazev, O. A., Stefanovsky, S. V., ICEM'971nt. Conf, Sept. 11-16, 1997, p. 333, Singapore 1997.
19. Idenbom, V. L., Crystallography, 5, 115 (1960).
20. Coehlo, A. A., Cheary, R. W., Smith, K. L., J. Sol. State Chem. 129, 246 (1997).

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed