Mössbauer Spectroscopy of Annealed Metamict Gadolinite REE2Fe2+Be2Si2O10 from 473 to 873 K in Air
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Abstract
The effect of medium-temperature annealing on fully metamict gadolinite was studied using Mössbauer spectroscopy. Metamict minerals contain radioactive elements that degrade their crystal structure. Mössbauer spectra for samples annealed at 473, 573, 673, and 773 K can be fitted to two Fe2+ quadrupole doublets and do not show the presence of a Fe3+ component. After heating at 773 K, an increase in the quadrupole splitting of the first Fe2+ component and the line width of both Fe2+ components is observed. The Fe3+ component appears after annealing at 873 K.
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