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silanol

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Journal Article

CHARACTERIZATION OF SILANOL GROUPS IN PROTONATED MAGADIITE BY 1 H AND 2 H SOLID-STATE NUCLEAR MAGNETIC RESONANCE

Yoshihiko Komori, Masaki Miyoshi, Shigenobu Hayashi, Yoshiyuki Sugahara, Kazuyuki Kuroda
Published: 01 December 2000
Clays and Clay Minerals (2000) 48 (6): 632–637.
...Yoshihiko Komori; Masaki Miyoshi; Shigenobu Hayashi; Yoshiyuki Sugahara; Kazuyuki Kuroda Abstract Silanol groups in protonated magadiite (H-magadiite) were characterized by 1 H and 2 H solid-state nuclear magnetic resonance (NMR). H-magadiite and deuterated (D) magadiite were synthesized...
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29 Si CPMAS NMR investigations of silanol-group minerals and hydrous aluminosilicate glasses

Jane V. Oglesby, Jonathan F. Stebbins
Published: 01 May 2000
American Mineralogist (2000) 85 (5-6): 722–731.
DOI: https://doi.org/10.2138/am-2000-5-610
...Jane V. Oglesby; Jonathan F. Stebbins Abstract One-pulse magic angle spinning (MAS) 29 Si and 1 H- 29 Si cross-polarization (CP) MAS nuclear magnetic resonance (NMR) spectroscopy was performed on minerals with OH groups and on hydrous aluminosilicate glass samples. The silanol-group samples used...
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Silanol groups in minerals and inorganic compounds

Daniel Nyfeler, Thomas Armbruster
Published: 01 February 1998
American Mineralogist (1998) 83 (1-2): 119–125.
DOI: https://doi.org/10.2138/am-1998-1-211
... of the silanol group is overbonded to satisfy the charge requirements of Si (super 4+) . In contrast, an Si-OH bearing tetrahedron with three bridging O atoms is characterized by a more regular bond strength distribution consistent with minor bond length distortion. GeoRef, Copyright 2004, American Geological...
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Hydrogen bonded silanols in the 10 Å phase: Evidence from NMR spectroscopy

Brian L. Phillips, Harris E. Mason, Stephen Guggenheim
Published: 01 August 2007
American Mineralogist (2007) 92 (8-9): 1474–1485.
DOI: https://doi.org/10.2138/am.2007.2417
... to silanol groups that donate hydrogen bonds to interlayer H 2 O. 29 Si NMR spectra of 10 Å phase samples synthesized from oxide and from crystalline talc starting materials contain a peak near −87 ppm for Q 2 Si, in addition to the main peak at −98 ppm for the talc-like Q 3 of the tetrahedral sheet. The 1...
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Plot of the area under the band at 4500 cm −1 (attributed to <span class="search-highlight">silanol</span> group...

Plot of the area under the band at 4500 cm −1 (attributed to silanol group...

Published: 01 June 2017
Fig. 3 Plot of the area under the band at 4500 cm −1 (attributed to silanol groups) as a function of the position of the apparent maximum near 5200 cm −1 (attributed to molecular water). Opal-CT (triangle), chalcedony (square) and opal-A (circle) define separate groups with no overlapping
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Geometry and magnitude of the surface dipole in a <span class="search-highlight">silanol</span> group at a silica...

Geometry and magnitude of the surface dipole in a silanol group at a silica...

Published: 01 January 2013
Figure 15 Geometry and magnitude of the surface dipole in a silanol group at a silica surface.
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The water network of the inter-layer region of RUB-18 made up by <span class="search-highlight">silanol</span>&#x2F;si...

The water network of the inter-layer region of RUB-18 made up by silanol/si...

Published: 01 June 2012
Fig. 13 The water network of the inter-layer region of RUB-18 made up by silanol/siloxy-groups of the layer and water molecules of the [Na(H 2 O) 6 ] + octahedra. Hydrogen bonds are shown as dashed blue lines, Na-O bonds are shown as yellow lines. Si (purple), O (red), OH/O − (dark blue), H 2 O
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Comparison of spectra derived from molecular water (A–C) and <span class="search-highlight">silanol</span> group ...

Comparison of spectra derived from molecular water (A–C) and silanol group ...

Published: 01 April 2008
Figure 8 Comparison of spectra derived from molecular water (A–C) and silanol group (D–F) in opal-A and opal-CT based on statistics derived from 20 opal-A spectra and 16 opal-CT spectra. SEM = standard error of the mean. Boxes around the mean show plus and minus twice the SEM. Mean values
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The surface of hydroxylised amorphous silica, after a model of Garofalini ...

The surface of hydroxylised amorphous silica, after a model of Garofalini ...

Published: 01 May 2007
Fig. 1. The surface of hydroxylised amorphous silica, after a model of Garofalini (1990) . Gray circles: silicon atoms, dark gray circles: bridging oxygens (siloxanes), oblique hatching: terminal silanols, horizontal hatching: geminal silanols.
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Enlarged microstructures of various defect types (Si 1 , Si 2 , Si 3 and S...

Enlarged microstructures of various defect types (Si 1 , Si 2 , Si 3 and S...

Published: 24 May 2019
Fig. 2. Enlarged microstructures of various defect types (Si 1 , Si 2 , Si 3 and Si 4 ) created at the tetrahedral SiO 4 surface. O h is from the hydroxyl of silanol and O a (bridging O) is also bonded to the silanol Si atom, while O b (bridging O) has no relation to the defect sites.
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( a ) A plot of the cross-polarization time constants (τ SiH ) vs. the sila...

( a ) A plot of the cross-polarization time constants (τ SiH ) vs. the sila...

Published: 01 May 2000
F igure 4. ( a ) A plot of the cross-polarization time constants (τ SiH ) vs. the silanol (or minimum) Si-H distance, r SiH , for each silicon site in the mineral structures shown with a fit to the data with τ SiH proportional to r SiH 3 . Values for the silanol sites are represented
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Best DFT model obtained for (a) minimal H 3 SiO − cluster with two adsorbe...

Best DFT model obtained for (a) minimal H 3 SiO − cluster with two adsorbe...

Published: 01 May 2007
Fig. 9. Best DFT model obtained for (a) minimal H 3 SiO − cluster with two adsorbed water molecules; (b) glycine adsorbed on SiO − ; (c) silanolate in a 5R ring, with an additional water molecule; (d) glycine on a 5R ring bearing a silanolate group. Note the participation of one water molecule
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Best DFT model of (a) Gly/SiO 2 in anhydrous conditions, such as may be ob...

Best DFT model of (a) Gly/SiO 2 in anhydrous conditions, such as may be ob...

Published: 01 May 2007
Fig. 8. Best DFT model of (a) Gly/SiO 2 in anhydrous conditions, such as may be obtained by CVD procedures. Narrow lines indicate the network of hydrogen bonds; the H-bond contact distances are indicated; (b) silanols with two water molecules; (c) zwitterionic glycine on silanols with two
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Representative FTIR spectra of opal. Component bands deconvoluted from prim...

Representative FTIR spectra of opal. Component bands deconvoluted from prim...

Published: 01 April 2008
bands 1 + 2 and 3 + 4 represent Type A and B molecular water, respectively. Summation of component bands has R 2 > 0.999. C, D) FTIR spectra between 4250 cm −1 and 4650 cm −1 showing silanol bands in opal-A (C) and opal-CT (D) in vitreous sinter from Waikite Geyser complex. Component bands 1
Journal Article

The crystal structure of mineral magadiite, Na 2 Si 14 O 28 (OH) 2 ∙8H 2 O

Bernd Marler, Yaşar Krysiak, Isabel Grosskreuz, Hermann Gies, Ute Kolb
Published: 01 November 2022
American Mineralogist (2022) 107 (11): 2101–2110.
DOI: https://doi.org/10.2138/am-2022-8156
... O atoms) and possess a silicon Q 4 to Q 3 ratio of 2.5. 16 out of 32 terminal silanol groups are protonated, and the remaining groups compensate for the charge of the hydrated sodium cations. Bands of edge-sharing [Na(H 2 O) 6/1.5 ] octahedra are intercalated between the silicate layers extending...
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Variations in Water Content in Opal-A and Opal-CT from Geyser Discharge Aprons

Rachel Day, Brian Jones
Published: 01 April 2008
Journal of Sedimentary Research (2008) 78 (4): 301–315.
DOI: https://doi.org/10.2110/jsr.2008.030
...Figure 8 Comparison of spectra derived from molecular water (A–C) and silanol group (D–F) in opal-A and opal-CT based on statistics derived from 20 opal-A spectra and 16 opal-CT spectra. SEM = standard error of the mean. Boxes around the mean show plus and minus twice the SEM. Mean values...
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Infrared spectra in the region of the specific moganite-band near 570 cm −1...

Infrared spectra in the region of the specific moganite-band near 570 cm −1...

Published: 01 December 2013
Fig. 6 Infrared spectra in the region of the specific moganite-band near 570 cm −1 in sample GC-11-16a before (a) and after heat treatment at 700 °C (b). The band actually observed in the spectra is composed of two components, the LF-chalcedony silanol-band at 555 cm −1 and the moganite-band
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Comparison of the crystal structures of rosenhahnite and trabzonite. ( a ) ...

Comparison of the crystal structures of rosenhahnite and trabzonite. ( a ) ...

Published: 01 June 2012
in silanol groups are small grey spheres, hydrogen bonds are indicated in lilac. ( b ) The crystal structure of trabzonite projected along [011], with colours as above. The OH groups, other than those in silanol groups, are shown as light blue spheres.
Journal Article

A re-examination of water in agate and its bearing on the agate genesis enigma

Terry Moxon
Published: 01 October 2017
Mineralogical Magazine (2017) 81 (5): 1223–1244.
DOI: https://doi.org/10.1180/minmag.2017.081.002
...Terry Moxon Abstract Dehydration of silanol and molecular water in 60 agates from 12 hosts with ages between 23 to 2717 Ma has been investigated using desiccators and high-temperature furnace heating. There are wide differences in the water data obtained under uncontrolled and fixed atmospheric...
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A solid state 29 Si nuclear magnetic resonance study of opal and other hydrous silicas

Stuart J. Adams, Geoffrey E. Hawkes, Eirian H. Curzon
Published: 01 December 1991
American Mineralogist (1991) 76 (11-12): 1863–1871.
... not distinguish among opal-AG, opal-C, or opal-CT. However, the 29 Si line widths decrease with increasing structural order—opal-AG 9.8–9.9 ppm (two examples), opal-CT 6.0–7.5 ppm (12 examples), and opal-C < 5 ppm (one example)—and may be used to discriminate among these three phases. Most samples show silanol...
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