Details
| Original language | English |
|---|---|
| Pages (from-to) | 67-82 |
| Number of pages | 16 |
| Journal | European journal of mineralogy |
| Volume | 9 |
| Issue number | 1 |
| Publication status | Published - 30 Dec 1996 |
Abstract
Fe-staurolite synthesized in the pressure range 5 to 25 kbar at 680 °C was analysed by microprobe and by a titration method (for water-contents) which uses the "Karl-Fischer" reaction and also characterized by FT-infrared powder spectroscopy in the OH-stretching region (3000-4000 cm-1). The study shows that the stoichiometry of the synthetic Fe-staurolites depends on the pressure of equilibration, with Fe pfu decreasing with increasing pressure, according to the heterovalent substitution of Fe2+ by Al3+ in the T2 site. This charge-increasing substitution is combined with charge-reducing substitutions in the "kyanite"-layer and by vacancies in the proton site H1. The incorporation of Al in T2 is supported by peculiarities of the IR-spectra in the range of the OH-valence vibrations. Mg- and Zn-staurolite were synthesized at 25 kbar and 700 °C and investigated by infrared spectroscopy. The comparison of the infrared spectra of synthetic Fe-, Mg- and Zn-staurolites shows that there is a significant amount of Fe2+, Mg and Zn in the respective M2 sites.
Keywords
- Infrared spectroscopy, Karl-Fischer titration, OH-stretching region, Staurolite stoichiometry, Synthetic staurolites
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- Geochemistry and Petrology
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In: European journal of mineralogy, Vol. 9, No. 1, 30.12.1996, p. 67-82.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Crystal chemistry and infrared spectroscopy in the OH-stretching region of synthetic staurolites
AU - Koch-Müller, Monika
AU - Langer, Klaus
AU - Behrens, Harald
AU - Schuck, Götz
PY - 1996/12/30
Y1 - 1996/12/30
N2 - Fe-staurolite synthesized in the pressure range 5 to 25 kbar at 680 °C was analysed by microprobe and by a titration method (for water-contents) which uses the "Karl-Fischer" reaction and also characterized by FT-infrared powder spectroscopy in the OH-stretching region (3000-4000 cm-1). The study shows that the stoichiometry of the synthetic Fe-staurolites depends on the pressure of equilibration, with Fe pfu decreasing with increasing pressure, according to the heterovalent substitution of Fe2+ by Al3+ in the T2 site. This charge-increasing substitution is combined with charge-reducing substitutions in the "kyanite"-layer and by vacancies in the proton site H1. The incorporation of Al in T2 is supported by peculiarities of the IR-spectra in the range of the OH-valence vibrations. Mg- and Zn-staurolite were synthesized at 25 kbar and 700 °C and investigated by infrared spectroscopy. The comparison of the infrared spectra of synthetic Fe-, Mg- and Zn-staurolites shows that there is a significant amount of Fe2+, Mg and Zn in the respective M2 sites.
AB - Fe-staurolite synthesized in the pressure range 5 to 25 kbar at 680 °C was analysed by microprobe and by a titration method (for water-contents) which uses the "Karl-Fischer" reaction and also characterized by FT-infrared powder spectroscopy in the OH-stretching region (3000-4000 cm-1). The study shows that the stoichiometry of the synthetic Fe-staurolites depends on the pressure of equilibration, with Fe pfu decreasing with increasing pressure, according to the heterovalent substitution of Fe2+ by Al3+ in the T2 site. This charge-increasing substitution is combined with charge-reducing substitutions in the "kyanite"-layer and by vacancies in the proton site H1. The incorporation of Al in T2 is supported by peculiarities of the IR-spectra in the range of the OH-valence vibrations. Mg- and Zn-staurolite were synthesized at 25 kbar and 700 °C and investigated by infrared spectroscopy. The comparison of the infrared spectra of synthetic Fe-, Mg- and Zn-staurolites shows that there is a significant amount of Fe2+, Mg and Zn in the respective M2 sites.
KW - Infrared spectroscopy
KW - Karl-Fischer titration
KW - OH-stretching region
KW - Staurolite stoichiometry
KW - Synthetic staurolites
UR - http://www.scopus.com/inward/record.url?scp=0030753316&partnerID=8YFLogxK
U2 - 10.1127/ejm/9/1/0067
DO - 10.1127/ejm/9/1/0067
M3 - Article
AN - SCOPUS:0030753316
VL - 9
SP - 67
EP - 82
JO - European journal of mineralogy
JF - European journal of mineralogy
SN - 0935-1221
IS - 1
ER -