Crystal chemistry of the ulvöspinel-qandilite series.
In: American Mineralogist, Jg. 99 (2014-04-01), Heft 4, S. 847
academicJournal
Zugriff:
Five spinel single-crystal samples within the ulvöspinel-qandilite series [(Fe2-xMgx)TiO4, 0.15 < x < 0.94] were synthesized and structurally and chemically characterized by X-ray diffraction and electron microprobe techniques. Site populations, derived from structural and chemical analysis, show that the tetrahedrally coordinated site (T) is exclusively populated by Mg2+ and Fe2+, while the octahedrally coordinated site (M) is populated by Ti4+, Mg2+, Fe2+, and minor amounts of Fe3+. The inverse cation distribution is characterized by parallel substitution of Mg2+ for Fe2+ at both the T and M sites along the series. The variation in the unit-cell parameter from 8.527 to 8.495 Å is mainly related to the occurrence of Mg2+ at the M site rather than the T site. In fact, the substitution of Mg2+ for Fe2+ significant variations in M-O (from 2.045 to 2.034 Å) and only limited variation in T-O (from 2.007 to 2.002 Å). In conjunction with data from the literature, the present study provide a basis for quantitative analyses of the variation in TMg-O bond distance from 1.966 Å for Mg-poor ulvöspinel to 1.990 Å for the qandilite end-member. [ABSTRACT FROM AUTHOR]
Titel: |
Crystal chemistry of the ulvöspinel-qandilite series.
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Autor/in / Beteiligte Person: | BOSI, FERDINANDO ; HÅLENIUS, ULF ; SKOGBY, HENRIK |
Zeitschrift: | American Mineralogist, Jg. 99 (2014-04-01), Heft 4, S. 847 |
Veröffentlichung: | 2014 |
Medientyp: | academicJournal |
ISSN: | 0003-004X (print) |
DOI: | 10.2138/am.2014.4722 |
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