Abstract
A new high-pressure form of topaz-OH (denoted here topaz-OH II) was obtained at 14 GPa and 1400 °C. The X-ray diffraction patternof this phase can be indexed by an orthorhombic cell with a = 4.72318(5), b = 8.91480(9), and c = 2.77276(3) Å. The lengths of a andb are similar, but c is approximately a third of that for a previously reported topaz-OH (denoted topaz-OH I). The structural formula of topaz-OH II can be written as (Al 0.68Si0.32(O0.66(OH)0.34) 2, suggesting significant cation disorder in the structure. The crystal structure of topaz-OH II is solved using powder synchrotron X-ray diffraction data, and refined with constraints provided by a separate multi-nuclear NMR study. The structure has similarities with topaz-OH I and diaspore (α-AlOOH) structures, having partially occupied double edge-shared octahedral chains, and 2 × 1 tunnels with partially occupied tetrahedral and octahedral sites.
| Original language | English |
|---|---|
| Pages (from-to) | 1349-1352 |
| Number of pages | 4 |
| Journal | American Mineralogist |
| Volume | 95 |
| Issue number | 8-9 |
| DOIs | |
| Publication status | Published - Aug 2010 |
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Keywords
- Crystal structure
- High-pressure studies
- Order-disorder
- Phase transition
ASJC Scopus subject areas
- Geochemistry and Petrology
- Geophysics
Cite this
Crystal structure of a new high-pressure polymorph of topaz-OH. / Kanzaki, Masami.
In: American Mineralogist, Vol. 95, No. 8-9, 08.2010, p. 1349-1352.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Crystal structure of a new high-pressure polymorph of topaz-OH
AU - Kanzaki, Masami
PY - 2010/8
Y1 - 2010/8
N2 - A new high-pressure form of topaz-OH (denoted here topaz-OH II) was obtained at 14 GPa and 1400 °C. The X-ray diffraction patternof this phase can be indexed by an orthorhombic cell with a = 4.72318(5), b = 8.91480(9), and c = 2.77276(3) Å. The lengths of a andb are similar, but c is approximately a third of that for a previously reported topaz-OH (denoted topaz-OH I). The structural formula of topaz-OH II can be written as (Al 0.68Si0.32(O0.66(OH)0.34) 2, suggesting significant cation disorder in the structure. The crystal structure of topaz-OH II is solved using powder synchrotron X-ray diffraction data, and refined with constraints provided by a separate multi-nuclear NMR study. The structure has similarities with topaz-OH I and diaspore (α-AlOOH) structures, having partially occupied double edge-shared octahedral chains, and 2 × 1 tunnels with partially occupied tetrahedral and octahedral sites.
AB - A new high-pressure form of topaz-OH (denoted here topaz-OH II) was obtained at 14 GPa and 1400 °C. The X-ray diffraction patternof this phase can be indexed by an orthorhombic cell with a = 4.72318(5), b = 8.91480(9), and c = 2.77276(3) Å. The lengths of a andb are similar, but c is approximately a third of that for a previously reported topaz-OH (denoted topaz-OH I). The structural formula of topaz-OH II can be written as (Al 0.68Si0.32(O0.66(OH)0.34) 2, suggesting significant cation disorder in the structure. The crystal structure of topaz-OH II is solved using powder synchrotron X-ray diffraction data, and refined with constraints provided by a separate multi-nuclear NMR study. The structure has similarities with topaz-OH I and diaspore (α-AlOOH) structures, having partially occupied double edge-shared octahedral chains, and 2 × 1 tunnels with partially occupied tetrahedral and octahedral sites.
KW - Crystal structure
KW - High-pressure studies
KW - Order-disorder
KW - Phase transition
UR - http://www.scopus.com/inward/record.url?scp=77957298498&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77957298498&partnerID=8YFLogxK
U2 - 10.2138/am.2010.3555
DO - 10.2138/am.2010.3555
M3 - Article
AN - SCOPUS:77957298498
VL - 95
SP - 1349
EP - 1352
JO - American Mineralogist
JF - American Mineralogist
SN - 0003-004X
IS - 8-9
ER -