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cotunnite

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Journal Article

A cotunnite-type new high-pressure phase of Fe 2 S Available to Purchase

Kenta Oka, Shigehiko Tateno, Yasuhiro Kuwayama, Kei Hirose, Yoichi Nakajima, Koihiro Umemoto, Noriyoshi Tsujino, Saori I. Kawaguchi
Published: 01 July 2022
American Mineralogist (2022) 107 (7): 1249–1253.
DOI: https://doi.org/10.2138/am-2022-7959
...-anvil cell. Fe 2 S is not stable at ambient pressure but is known to form above 21 GPa with the Fe 2 P-type (C22) structure. Our experiments demonstrate a novel phase transition in Fe 2 S from the C22 to C23 phase with the Co 2 P-type cotunnite structure above ~30 GPa. The experiments also reveal...
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View PDF for article title, A <span class="search-highlight">cotunnite</span>-type new high-pressure phase of Fe 2 S
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Examples of measured X-ray diffraction patterns with background subtraction (black lines) along with fits (red lines) and residuals (blue lines) obtained from Rietveld refinements. The omitted intensity between 14.5° and 15.5° is due to the angled part of the cBN seat and not included in the structural refinement. The vertical bars represent peak positions obtained from structural refinements. (a) Example of diffraction pattern from the OI structure obtained on initial compression to 34.5 GPa of the starting material. A small amount of baddeleyite-structured material helps account for the shoulders around the most intense line. (b) Cotunnite structure obtained at 39 GPa post-heating at ~1500 K. The changes in diffraction patterns and peak sharpening from a to b are typical after only a few minutes of laser heating (see Fig. 4 as well). (c) Cotunnite structure compressed to 105 GPa at room temperature without laser heating of the sample. (d) Post-heating diffraction of c, resulting in significant sharpening of the cotunnite-type phase reflections (e) Pyrite-type structure with minor amounts of baddeleyite and OI type phases formed on decompression of the cotunnite-type phase from 24 to 10.5 GPa. (f) Unheated PbO2 in the α structure after room-temperature decompression from e at 10.5 GPa. (Color online.)

Examples of measured X-ray diffraction patterns with background subtraction... Available to Purchase

Published: 01 January 2014
for the shoulders around the most intense line. ( b ) Cotunnite structure obtained at 39 GPa post-heating at ~1500 K. The changes in diffraction patterns and peak sharpening from a to b are typical after only a few minutes of laser heating (see Fig. 4 as well). ( c ) Cotunnite structure compressed to 105 GPa
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(a) Fluorite crystal structure. (b) Cotunnite-type crystal structure. Green spheres represent the Th4+ cations, red spheres represent the O2– anions. (Color online.)

( a ) Fluorite crystal structure. ( b ) Cotunnite-type crystal structure. G... Available to Purchase

Published: 01 May 2018
Figure 1. ( a ) Fluorite crystal structure. ( b ) Cotunnite-type crystal structure. Green spheres represent the Th 4+ cations, red spheres represent the O 2– anions. (Color online.)
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Measured P-V-T data for thorianite and cotunnite-type ThO2. Curves are isotherms calculated using the equation of state parameters from Table 1. Isotherms are color-coded by temperature. Residuals to the fits are provided in the bottom panels. (Color online.)

Measured P-V-T data for thorianite and cotunnite-type ThO 2 . Curves are ... Available to Purchase

Published: 01 May 2018
Figure 7. Measured P-V-T data for thorianite and cotunnite-type ThO 2 . Curves are isotherms calculated using the equation of state parameters from Table 1 . Isotherms are color-coded by temperature. Residuals to the fits are provided in the bottom panels. (Color online.)
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Individual lattice parameters and their ratios for cotunnite-type ThO2. Black lines are linear fits to the data. No temperature dependence was resolved for the lattice parameter ratios. (Color online.)

Individual lattice parameters and their ratios for cotunnite-type ThO 2 . B... Available to Purchase

Published: 01 May 2018
Figure 8. Individual lattice parameters and their ratios for cotunnite-type ThO 2 . Black lines are linear fits to the data. No temperature dependence was resolved for the lattice parameter ratios. (Color online.)
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Crystal structure model of the cotunnite-type phase in PbO2 looking close to straight down the c-axis. Red spheres are oxygen atoms and black spheres are lead atoms. The ninefold-coordinated structure consists of three sets of bonds with a twofold multiplicity labeled 2, 5, and 6. Bonds 1, 3, and 4 have a multiplicity of one. The oxygen network is a distorted hcp lattice that forms kinked chains of coordinating polyhedra. (Color online.)

Crystal structure model of the cotunnite-type phase in PbO 2 looking close... Available to Purchase

Published: 01 January 2014
Figure 5 Crystal structure model of the cotunnite-type phase in PbO 2 looking close to straight down the c -axis. Red spheres are oxygen atoms and black spheres are lead atoms. The ninefold-coordinated structure consists of three sets of bonds with a twofold multiplicity labeled 2, 5, and 6
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Pb-O bond lengths from structural refinements of cotunnite structure and Pb-Pb-Pb angles. Most Pb-O bond distances decrease rapidly with pressure, before flattening out at even higher pressure. The trend is to have more uniform bond distances, although there is still appreciable scatter from the refinements. The Pb-Pb-Pb angles become slightly less regular with pressure. (Color online.)

Pb-O bond lengths from structural refinements of cotunnite structure and Pb... Available to Purchase

Published: 01 January 2014
Figure 6 Pb-O bond lengths from structural refinements of cotunnite structure and Pb-Pb-Pb angles. Most Pb-O bond distances decrease rapidly with pressure, before flattening out at even higher pressure. The trend is to have more uniform bond distances, although there is still appreciable scatter
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Measured unit-cell volumes for OI (Z = 8) and cotunnite (Z = 4) phases. The error is smaller than the size of the data points (Table 2). The volume change at the transition (24 GPa) is 11%, consistent with other analogs such as ZrO2 (Ohtaka et al. 2001). Dashed lines are fits to the second-order Birch Murnaghan EOS. This yields a K0 = 219(1) GPa with V0 = 134.4(3) Å3 for the cotunnite structure and K0 = 122(7) GPa with V0 = 313.8(1.9) Å3 for the OI structure.

Measured unit-cell volumes for OI ( Z = 8) and cotunnite ( Z = 4) phases.... Available to Purchase

Published: 01 January 2014
Figure 9 Measured unit-cell volumes for OI ( Z = 8) and cotunnite ( Z = 4) phases. The error is smaller than the size of the data points ( Table 2 ). The volume change at the transition (24 GPa) is 11%, consistent with other analogs such as ZrO 2 ( Ohtaka et al. 2001 ). Dashed lines are fits
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Images of burnsite grains (dark) in intimate intergrowth with cotunnite (light). Images obtained by scanning electron microscopy. Scale bar: 20 μm.

Images of burnsite grains (dark) in intimate intergrowth with cotunnite (li... Available to Purchase

Published: 01 August 2002
F ig . 1. Images of burnsite grains (dark) in intimate intergrowth with cotunnite (light). Images obtained by scanning electron microscopy. Scale bar: 20 μm.
Journal Article

New high-pressure phase relations in CaSnO 3 Available to Purchase

Taku Tsuchiya, Jun Tsuchiya
Published: 01 November 2006
American Mineralogist (2006) 91 (11-12): 1879–1887.
DOI: https://doi.org/10.2138/am.2006.2221
...Taku Tsuchiya; Jun Tsuchiya Abstract High-pressure phase stabilities of the CaSnO 3 system were investigated using density functional theory static lattice energy calculations. We have identified six phase changes in this system: perovskite-post-perovskite, post-perovskite-B2+cotunnite in CaSiO 3...
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Journal Article

High-pressure phase behavior and equations of state of ThO 2 polymorphs Available to Purchase

Bethany A. Chidester, Olivia S. Pardo, Rebecca A. Fischer, Elizabeth C. Thompson, Dion L. Heinz, Clemens Prescher, Vitali B. Prakapenka, Andrew J. Campbell
Published: 01 May 2018
American Mineralogist (2018) 103 (5): 749–756.
DOI: https://doi.org/10.2138/am-2018-6212
...Figure 1. ( a ) Fluorite crystal structure. ( b ) Cotunnite-type crystal structure. Green spheres represent the Th 4+ cations, red spheres represent the O 2– anions. (Color online.) ...
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View PDF for article title, High-pressure phase behavior and equations of state of ThO 2 polymorphs
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Lattice parameters from our data set (filled) and from Haines et al. (1996) (open). Dashed lines are fits to the unit-cell parameters that are back-extrapolated to room pressure for the cotunnite-type structure using the method in Xia et al. (1998). This yields a0 = 5.663(4), b0 = 6.670(4), c0 = 3.563(3). The cotunnite-type structure has close to isotropic compression. The compressibility is in contrast to the OI structure, where the b axis is much stiffer than the a or c axes (see Table 3). The a/c ratio is shown, which increases and levels off like ZrO2 (Ohtaka et al. 2001) and SnO2 (Shieh et al. 2005). The a/c ratio for flouride compounds such as CaF2 (open blue cirlces) has a decrease when approaching the post-cotunnite transition (Dorfman et al. 2010). Although the decrease in our ratio above 120 GPa is slight, it may be an early indication of a phase transition at slightly higher pressure. (Color online.)

Lattice parameters from our data set (filled) and from Haines et al. (1996... Available to Purchase

Published: 01 January 2014
Figure 7 Lattice parameters from our data set (filled) and from Haines et al. (1996) (open). Dashed lines are fits to the unit-cell parameters that are back-extrapolated to room pressure for the cotunnite-type structure using the method in Xia et al. (1998) . This yields a 0 = 5.663(4), b
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Stability diagram for high-pressure phases of PbO2. Blue denotes where the cotunnite-type (Pnam) phase is found, red for OI-type (Pbca), green for trace baddeleyite-type (P21/c), pink for pyrite-type (Pa3̄), and black for the α-structure (Pbcn). Circles denote the stable phase during and after heating, triangles denote stable phases during cold compression or post-annealing decompression, and crosses denote where there is evidence of melting. The pressure values are from the room-temperature measurements and so we have used asymmetric error bars to account for the likely effect of thermal pressure at high temperature. Experimental values for cold compression and decompression from Haines et al. (1996) are presented at the bottom. The cotunnite transition is hindered at low pressure, with the OI phase remaining metastable well into the stability field of the cotunnite-type phase. Heating (this study) or shear stress (Haines et al. 1996) may produce the high-pressure phase, although with the latter method a large modal fraction remains in the OI structure. (Color online.)

Stability diagram for high-pressure phases of PbO 2 . Blue denotes where th... Available to Purchase

Published: 01 January 2014
Figure 1 Stability diagram for high-pressure phases of PbO 2 . Blue denotes where the cotunnite-type ( Pnam ) phase is found, red for OI-type ( Pbca ), green for trace baddeleyite-type ( P 2 1 /c ), pink for pyrite-type ( Pa 3̄), and black for the α-structure ( Pbcn ). Circles denote the stable
Journal Article

Crystal structure and compressibility of lead dioxide up to 140 GPa Available to Purchase

Brent Grocholski, Sang-Heon Shim, Elizabeth Cottrell, Vitali B. Prakapenka
Published: 01 January 2014
American Mineralogist (2014) 99 (1): 170–177.
DOI: https://doi.org/10.2138/am.2014.4596
... for the shoulders around the most intense line. ( b ) Cotunnite structure obtained at 39 GPa post-heating at ~1500 K. The changes in diffraction patterns and peak sharpening from a to b are typical after only a few minutes of laser heating (see Fig. 4 as well). ( c ) Cotunnite structure compressed to 105 GPa...
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Journal Article

HEPHAISTOSITE, TlPb 2 Cl 5 , A NEW THALLIUM MINERAL SPECIES FROM LA FOSSA CRATER, VULCANO, AEOLIAN ISLANDS, ITALY Available to Purchase

Italo Campostrini, Francesco Demartin, Carlo Maria Gramaccioli, Paolo Orlandi
Published: 01 June 2008
The Canadian Mineralogist (2008) 46 (3): 701–708.
DOI: https://doi.org/10.3749/canmin.46.3.701
..., Italy. The mineral occurs as aggregates of pale yellow-green crystals tabular on {010} up to 0.1 mm in length on fragments of altered pyroclastic breccia, in association with bismuthinite (Bi 2 S 3 ), cotunnite (PbCl 2 ), challacolloite (KPb 2 Cl 5 ) and pseudocotunnite (K 2 PbCl 4 ). The mineral...
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View PDF for article title, HEPHAISTOSITE, TlPb 2 Cl 5 , A NEW THALLIUM MINERAL SPECIES FROM LA FOSSA CRATER, VULCANO, AEOLIAN ISLANDS, ITALY
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Journal Article

BURNSITE, KCdCu 7 O 2 (SeO 3 ) 2 Cl 9 , A NEW MINERAL SPECIES FROM THE TOLBACHIK VOLCANO, KAMCHATKA PENINSULA, RUSSIA Available to Purchase

Sergey V. Krivovichev, Lidiya P. Vergasova, Galina L. Starova, Stanislav K. Filatov, Sergey N. Britvin, Andrew C. Roberts, Ian M. Steele
Published: 01 August 2002
The Canadian Mineralogist (2002) 40 (4): 1171–1175.
DOI: https://doi.org/10.2113/gscanmin.40.4.1171
...F ig . 1. Images of burnsite grains (dark) in intimate intergrowth with cotunnite (light). Images obtained by scanning electron microscopy. Scale bar: 20 μm. ...
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View PDF for article title, BURNSITE, KCdCu 7 O 2 (SeO 3 ) 2 Cl 9 , A NEW MINERAL SPECIES FROM THE TOLBACHIK VOLCANO, KAMCHATKA PENINSULA, RUSSIA
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Journal Article

Structural characterization of natural UO 2 at pressures up to 82 GPa and temperatures up to 2200 K Available to Purchase

Steeve Gréaux, Laurent Gautron, Denis Andrault, Nathalie Bolfan-Casanova, Nicolas Guignot, Julien Haines
Published: 01 July 2008
American Mineralogist (2008) 93 (7): 1090–1098.
DOI: https://doi.org/10.2138/am.2008.2735
... equation of state, we calculated room-pressure bulk modulus K 0 = 166(7) GPa with pressure derivative K ′ 0 = 4.0 for the Pa 3̅ structure, and K 0 = 225(8) GPa with K ′ 0 = 4 for the Pbca structure. The expected Pnma cotunnite structure was not observed but is not excluded at pressures higher than 82 GPa...
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View PDF for article title, Structural characterization of natural UO 2 at pressures up to 82 GPa and temperatures up to 2200 K
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Dissociation phase bound-ary in MgSiO3. PPV is predicted to dissociate into CsCl-type MgO and cotunnite-type SiO2. Rectangles denote estimated pressure-temperature conditions at core-envelope boundaries in the solar giants and in GJ876d.

Dissociation phase bound-ary in MgSiO 3 . PPV is predicted to dissociate in... Available to Purchase

Published: 01 January 2010
Figure 3. Dissociation phase bound-ary in MgSiO 3 . PPV is predicted to dissociate into CsCl-type MgO and cotunnite-type SiO 2 . Rectangles denote estimated pressure-temperature conditions at core-envelope boundaries in the solar giants and in GJ876d.
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XRD patterns in runs 1 (a and b) and 3 (d and e) collected at ~64 and ~164 GPa, showing the formation of the C23 cotunnite-type and C37 Fe2S phases upon heating, respectively. The calculated XRD patterns are given for the C23 (c) and C37 structures (f). sm = starting material.

XRD patterns in runs 1 ( a and b ) and 3 ( d and e ) collected at ~64 a... Available to Purchase

Published: 01 July 2022
Figure 1. XRD patterns in runs 1 ( a and b ) and 3 ( d and e ) collected at ~64 and ~164 GPa, showing the formation of the C23 cotunnite-type and C37 Fe 2 S phases upon heating, respectively. The calculated XRD patterns are given for the C23 ( c ) and C37 structures ( f ). sm = starting
Journal Article

Napoliite, Pb 2 OFCl, a new mineral from Vesuvius volcano, and its relationship with dimorphous rumseyite Available to Purchase

Anatoly V. Kasatkin, Oleg I. Siidra, Fabrizio Nestola, Igor V. Pekov, Atali A. Agakhanov, Natalia N. Koshlyakova, Nikita V. Chukanov, Evgeny V. Nazarchuk, Simone Molinari, Manuela Rossi
Published: 14 June 2023
Mineralogical Magazine (2023) 87 (5): 711–718.
DOI: https://doi.org/10.1180/mgm.2023.43
..., cerussite, challacolloite, cotunnite, hephaistosite, manuelarossiite, matlockite and susannite. Napoliite is colourless with white streak and adamantine lustre. It is brittle and has a laminated fracture. Cleavage is perfect on {001}. D calc = 7.797 g cm –3 . The calculated mean refractive index is 2.10...
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View PDF for article title, Napoliite, Pb 2 OFCl, a new mineral from Vesuvius volcano, and its relationship with dimorphous rumseyite
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