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intervalency charge transfer

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Journal Article
Published: 01 December 2024
American Mineralogist (2024) 109 (12): 2152–2161.
...Helen V. Evans; George R. Rossman Abstract Single-crystal optical spectra of corundum (Al 2 O 3 ) and the Al 2 SiO 5 polymorphs andalusite, kyanite, and sillimanite, containing both Fe 2+ -Fe 3+ and Fe 2+ -Ti 4+ intervalence charge transfer (IVCT) absorption bands were measured at temperatures up...
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First thumbnail for: <span class="search-highlight">Intervalence</span>...
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Journal Article
Published: 01 April 1986
American Mineralogist (1986) 71 (3-4): 599–602.
...George R. Rossman; Stephanie M. Mattson Abstract The color of yellow-green to yellow-brown Mn-rich elbaite tourmalines from Zambia and Nepal is controlled by Fe 2+ -Ti 4+ (brown) and Mn 2+ -Ti 4+ (yellow-green) intervalence charge transfer. The proposed Mn-Ti interaction responsible...
Journal Article
Published: 01 August 1974
American Mineralogist (1974) 59 (7-8): 868–870.
...George R. Rossman Abstract The optical spectra of green, white, and lavender jadeite have been studied. Ferric iron is responsible for the color in the green jadeite. It is proposed that ferrous-ferriciron intervalence charge transfer is responsible for the lavender color of jadeite. 1...
Journal Article
Published: 02 July 2025
American Mineralogist (2025)
...Helen V. Evans; George R. Rossman Abstract The absorption of light by Fe/Ti and Fe/Fe intervalence charge transfer (IVCT) bands has previously been found in aluminum oxide and Al 2 SiO 5 aluminosilicate minerals to decrease markedly at elevated temperatures. Given the abundance of iron at depth...
Journal Article
Published: 01 June 2023
American Mineralogist (2023) 108 (6): 1171–1181.
...Charles A. Geiger; Michail N. Taran Abstract The various intervalence charge transfer (IVCT) mechanisms that can occur in silicate garnet, general crystal-chemical formula {X 3 }[Y 2 ](Z 3 )O 12 , are not fully understood. The single-crystal UV/Vis/NIR absorption spectra of two different almandine...
FIGURES
First thumbnail for: Single-crystal UV&#x2F;Vis absorption spectroscopy...
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Fingerprint of the clay minerals. The ratio of intervalence charge transfer (IVCT) band III to band IV is plotted against the ratio of divalent and trivalent Fe in the structure. The smectites free of Fe2+ are located in point [0,0].
Published: 01 December 2004
Figure 7. Fingerprint of the clay minerals. The ratio of intervalence charge transfer (IVCT) band III to band IV is plotted against the ratio of divalent and trivalent Fe in the structure. The smectites free of Fe 2+ are located in point [0,0].
Journal Article
Published: 01 May 2007
American Mineralogist (2007) 92 (5-6): 753–760.
...Michail N. Taran; M. Darby Dyar; Stanislav S. Matsyuk Abstract A broad (FWHM ≈ 7300 cm −1 ) intense band at ~21 700 cm −1 in the optical absorption spectra of natural Fe 2+ , Fe 3+ -rich garnets is attributed to electronic intervalence charge-transfer transitions (IVCT), VIII Fe 2+ + VI Fe 3...
FIGURES
First thumbnail for: Optical absorption study of natural garnets of alm...
Second thumbnail for: Optical absorption study of natural garnets of alm...
Third thumbnail for: Optical absorption study of natural garnets of alm...
Journal Article
Published: 01 June 2010
The Canadian Mineralogist (2010) 48 (3): 597–613.
... of blue beryl is due to intervalence charge-transfer (IVCT) between Fe 2+ and Fe 3+ cations. The anisotropy of the optical absorption spectra suggest that if the mechanism responsible for the color in our samples is IVCT, the vector between the ions involved must be oriented approximately parallel to c...
FIGURES
First thumbnail for: CRYSTAL CHEMISTRY OF DARK BLUE AQUAMARINE FROM THE...
Second thumbnail for: CRYSTAL CHEMISTRY OF DARK BLUE AQUAMARINE FROM THE...
Third thumbnail for: CRYSTAL CHEMISTRY OF DARK BLUE AQUAMARINE FROM THE...
Journal Article
Published: 01 July 2005
American Mineralogist (2005) 90 (7): 1209–1212.
... −1 . With increasing pressure, both the crystal field and the charge transfer bands shift to higher frequencies. Whereas this is expected for the crystal field bands, this blue shift is surprising for an intervalence charge transfer band. Moreover, neither the crystal field nor the charge transfer...
FIGURES
First thumbnail for: Optical and near infrared spectra of ringwoodite t...
Second thumbnail for: Optical and near infrared spectra of ringwoodite t...
Third thumbnail for: Optical and near infrared spectra of ringwoodite t...
Journal Article
Published: 01 October 2000
The Canadian Mineralogist (2000) 38 (5): 1193–1199.
... indicating 0.30 wt.% H 2 O in the structure, is (Ca 0.96 Na 0.04 )(Mg 0.86 Al 0.06 Fe 2+ 0.05 Ti 4+ 0.02 )(Si 1.89 Al 0.11 )O 5.93 OH 0.07 . The unusual color is due to intervalence charge-transfer between Fe 2+ and Ti 4+ at the M 1 site, and is observed owing to the low overall concentration of Fe...
FIGURES
First thumbnail for: VIOLET-COLORED DIOPSIDE FROM SOUTHERN BAFFIN ISLAN...
Second thumbnail for: VIOLET-COLORED DIOPSIDE FROM SOUTHERN BAFFIN ISLAN...
Third thumbnail for: VIOLET-COLORED DIOPSIDE FROM SOUTHERN BAFFIN ISLAN...
Journal Article
Published: 01 December 1994
American Mineralogist (1994) 79 (11-12): 1215–1218.
... is centered at 7000 cm −1 , which is caused by the transition 5 E g → 5 T 2g of Fe 2+ in the dodecahedral site of the structure. (2) A broad band due to Fe 2+ → Fe 3+ intervalence charge transfer occurs at 14900 cm −1 . (3) A sharp increase in absorption above 20000 cm −1 probably results from O-Fe 3+ charge...
Journal Article
Published: 01 December 1977
American Mineralogist (1977) 62 (11-12): 1144–1157.
... is found to correlate to the amount of cations in the channels. Optical spectra provide a measure of the hexagonality of cordierite, but these measurements are not correlated with the distortion index, Δ. The color and pleochroism are suggested to arise from intervalence charge-transfer between octahedral...
Journal Article
Published: 01 January 2013
American Mineralogist (2013) 98 (1): 7–18.
... has a broad absorption band at 6500 cm −1 wavenumber attributed to intervalence charge transfer transition Ti 3+ +Ti 4+ → Ti 4+ +Ti 3+ . The reduction of Ti 4+ to Ti 3+ is charge balanced by the incorporation of H + . The Nb-doped rutile changed its color from light greenish-blue (untreated) to deep...
FIGURES
First thumbnail for: Coupled H and Nb, Cr, and V trace element behavior...
Second thumbnail for: Coupled H and Nb, Cr, and V trace element behavior...
Third thumbnail for: Coupled H and Nb, Cr, and V trace element behavior...
Journal Article
Published: 01 November 2006
American Mineralogist (2006) 91 (11-12): 1794–1801.
... in the crystallographic b -direction, we assign this band to an M1 Ti 3+ - T Ti 4+ intervalence charge transfer process. * E-mail: [email protected] 01 06 2006 17 11 2005 © 2006 American Mineralogist 2006 Crystal synthesis diopside optical spectroscopy pyroxene major and minor...
FIGURES
First thumbnail for: Titanium incorporation and VI Ti 3+ - IV Ti 4+ <sp...
Second thumbnail for: Titanium incorporation and VI Ti 3+ - IV Ti 4+ <sp...
Third thumbnail for: Titanium incorporation and VI Ti 3+ - IV Ti 4+ <sp...
Journal Article
Published: 01 April 2003
American Mineralogist (2003) 88 (4): 481–488.
.... The optical spectrum of barbosalite can be resolved into three peaks at 8985 cm −1 , 10980 cm −1 , and 14110 cm −1 . These positions correlate well with the two calculated spin-allowed d-d transitions at 8824 cm −1 and 11477 cm −1 , and with an intervalence charge transfer transition at about 14200 cm −1...
FIGURES
First thumbnail for: Electronic structure of Fe-bearing lazulites
Second thumbnail for: Electronic structure of Fe-bearing lazulites
Third thumbnail for: Electronic structure of Fe-bearing lazulites
Journal Article
Published: 01 September 2012
European Journal of Mineralogy (2012) 24 (5): 817–822.
... polarons to Fe 2+ –Fe 3+ intervalence-charge transfer and Fe 2+ d–d transitions with decreasing temperature. The loss in oscillator strength of PAH is related to a pinning of the polarons due to the decreasing number in lattice vibrations in thermal equilibrium. The absorption spectra of two natural...
FIGURES
First thumbnail for: Temperature-dependent absorption of biotite: small...
Second thumbnail for: Temperature-dependent absorption of biotite: small...
Third thumbnail for: Temperature-dependent absorption of biotite: small...
Journal Article
Published: 22 August 2022
Mineralogical Magazine (2022) 86 (6): 910–919.
...+ , and no intervalence charge transfer Fe 2+ -Ti interactions, indicating that Fe 2+ is the only chromophore. Mössbauer analysis of the blue zone of the Fucili sample confirmed the Fe 2+ oxidation state, implying that the redox conditions in the crystallisation environment were relatively reducing. The presence...
FIGURES
First thumbnail for: Blue growth zones caused by Fe 2+ in tourmaline cr...
Second thumbnail for: Blue growth zones caused by Fe 2+ in tourmaline cr...
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Journal Article
Journal: Clay Minerals
Published: 13 May 2020
Clay Minerals (2020) 55 (1): 83–95.
... . This chamosite is strongly pleochroic, from pale yellow ( E || (001)) to deep orange red ( E ⊥ (001)). Visible–near-infrared absorbance spectra show a specific absorption band centred at ~550 nm for E ⊥ (001), due to a proposed new variety of Fe/V intervalence charge-transfer mechanism in the octahedral sheet...
FIGURES
First thumbnail for: Polygenic chamosite from a hydrothermalized ooliti...
Second thumbnail for: Polygenic chamosite from a hydrothermalized ooliti...
Third thumbnail for: Polygenic chamosite from a hydrothermalized ooliti...
Journal Article
Published: 22 June 2015
The Canadian Mineralogist (2014) 52 (6): 1019–1026.
...-fluorescent with perfect {110} cleavage, no observable parting, and has a calculated density of 3.424 g/cm 3 . Crystals show extreme optical absorption due to intervalence charge transfer, which inhibited measurement of optical properties. Ferro-ferri-nybøite is monoclinic, space group C 2/ m , a 9.9190(5), b...
FIGURES
First thumbnail for: FERRO-FERRI-NYBØITE, NaNa 2 (Fe 2+ 3 Fe 3+ 2 )(Si ...
Journal Article
Published: 01 October 2013
Mineralogical Magazine (2013) 77 (7): 2941–2953.
...-forbidden electronic transitions in T Fe 2+ and to M Fe 2+ ↔ M Fe 3+ intervalence charge transfer, and the poor saturation of the colour is due to the small concentration of Fe 2+ and Fe 3+ . * E-mail: [email protected] 18 4 2013 13 8 2013 © 2013 The Mineralogical...
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First thumbnail for: Crystallographic and spectroscopic characterizatio...
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