ISSN:
1432-2021
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Chemie und Pharmazie
,
Geologie und Paläontologie
,
Physik
Notizen:
Abstract Mössbauer spectra of 57Fe in 2 schorlomite garnets reveal 5 distinct quadrupole-split doublets: dodecahedral Fe2+, octahedral Fe2+ and Fe3+, and tetrahedral Fe2+ and Fe3+. The isomer shifts and nuclear quadrupole splittings of the 5 doublets were studied between 15 and 500 K. The site occupancies for iron were determined. Reference of the chemical analyses to a basis of 12 oxygens and the Mössbauer data show that in the 2 schorlomites titanium is exclusively quadruvalent within the experimental error. The isomer shift of tetrahedral Fe2+ between 15 and 295 K seems to be rather small. The shift is interpreted in terms of localized chemical bonding. Above 295 K the shift cannot be evaluated because of overlapping peaks. If electronic transfer processes (e.g. “electron hopping”) between cations are present their relaxation times must be longer than ∼10−7 s.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00308849
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