Structural evolution of calcite at high temperatures: Phase V unveiled

Ishizawa, Nobuo; Setoguchi, Hayato; Yanagisawa, Kazumichi

doi:10.1038/srep02832

Cited by 67 publications

(89 citation statements)

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“…CaO + CO 2 (1) Bayarjargal et al (2010), however, proposed an alternative decomposition reaction on the basis of their experimental observation of diamond formation from calcite under high pressure and temperature, Isosurface plots of the joint-probability density function of the oxygen atoms in the carbonate group at selected temperatures, as in Figure 4 of the original paper (Ishizawa et al, 2013). The isosurface levels are the top 10, 50, and 90% probabilities from the interior.…”

Section: Resultsmentioning

confidence: 99%

“…Our recent study on the structural evolution of calcite at elevated temperatures (Ishizawa et al, 2013) appears to have solved an enduring mystery of over a hundred years, dating from the finding of a reversible phase transition of calcite by Boeke in 1912, and following W. L. Bragg's structure determination at room temperature in 1914. Crystals of calcite sealed in a silica glass capillary in a carbon dioxide atmosphere undergo reversible phase transitions between Phases I, IV, and V in this order with increasing temperature.…”

Section: Discussionmentioning

confidence: 99%

“…In this study, three methods were examined, as shown in Figure 1: (1) the sample (hs11) was mounted on top of a silica glass capillary with cement; (2) the sample (hs23) was sealed in a silica glass capillary in an air atmosphere; and (3) the sample (hs25) was sealed in a silica glass capillary in a carbon dioxide gas atmosphere. The experimental details are given in the original paper (Ishizawa et al, 2013). Structural analysis and volumetric plotting were done using the programs Jana2006 (Petricek et al, 2006) and Vesta (Momma and Izumi, 2011), respectively.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…This high-temperature phase, which was named as Phase V by Mirwald (1976), has been a key controversial issue in the field of common minerals for over a hundred years (Tsuboi, 1927;Mirwald, 1979;Markgraf and Reeder, 1985;Dove and Powell, 1989;Hagen et al, 1992;Maslen et al, 1993;Dove et al, 2005;Antao et al, 2009). The structure of Phase V was finally determined in our previous study (Ishizawa et al, 2013), and is briefly reviewed here, in addition to the intermediate Phase IV that bridges Phases I and V.…”

Section: Introductionmentioning

confidence: 99%

“…A 89,, the high-temperature Phase V of calcite has been an enduring mystery. Here, we summarize a paper on the structure of Phase V [Ishizawa, N., Setoguchi, H. and Yanagisawa, K. (2013). Sci.…”

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Calcite V: a hundred-year-old mystery has been solved

Ishizawa

2014

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Since Boeke's finding of a reversible phase transition of calcite (calcium carbonate, CaCO 3 ) at elevated temperatures [Boeke, H. E. (1912). Neues Jahrb. Mineral. 1, 91-121], and following W. L. Bragg's determination of the structure of the room-temperature Phase I [Bragg, W. L. (1914). Proc. R. Soc. Lond. A 89,, the high-temperature Phase V of calcite has been an enduring mystery. Here, we summarize a paper on the structure of Phase V [Ishizawa, N., Setoguchi, H. and Yanagisawa, K. (2013). Sci. Rep. 3, 2832], as well as the intermediate Phase IV which exists between Phases I and V, and add new aspects. An in situ single-crystal X-ray diffraction study revealed that the I-IV and IV-V transitions occurred reversibly at approximately 985 and 1240 K, respectively, in a carbon dioxide atmosphere. Phase V was stable only over a narrow temperature range between 1240 and 1275 K. The crystal decomposed immediately at temperatures above 1275 K, leaving a nanoporous calcium oxide reaction product which retained the shape of the parent calcite crystal. The I-IV transition can be described as an orientational order/disorder transition of the carbonate group, occurring within the same space group R 3c. In Phase V, the oxygen sublattice is melted. The joint-probability density function obtained from the anharmonic atomic displacement parameters of the oxygen atoms revealed that the oxygen triangles of the carbonate group in Phase V do not sit still at specified Wyckoff positions in the space group R 3m, but are instead distributed with equal probability along the undulated circular orbital about the central carbon. The carbonate group in Phase V is no longer flat on the basal plane when the oxygen triangle comes to troughs or peaks in the undulated orbital, but is instead deformed like an umbrella. Assuming that the oxygen triangle migrates about carbon, the carbonate group should repeat the umbrella inversion in Phase V as a function of time. Finally, possible thermal decomposition mechanisms of calcite are briefly discussed.

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Section: Resultsmentioning

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Section: Discussionmentioning

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Section: Experimental Methodsmentioning

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Section: Introductionmentioning

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Calcite V: a hundred-year-old mystery has been solved

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2014

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Phase Diagrams of Carbonate Materials at High Pressures, with Implications for Melting and Carbon Cycling in the Deep Earth

Litasov

Shatskiy

Podborodnikov

et al. 2020

Geophysical Monograph Series

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In this chapter, we review phase diagrams of alkali and alkaline earth carbonates at high pressures, particularly simple, binary, and ternary systems, which were recently constrained at pressures of 3 and 6 GPa. These studies revealed a number of new alkali-alkaline earth double carbonates. Major transformations of high-pressure carbonates, including changes in carbon coordination, spin transition, and valence state in Fe-bearing carbonates up to the lower mantle levels, were also discussed. We emphasize the importance of carbonate systems for understanding the low-degree partial melting of carbonated mantle rocks and explaining carbonate inclusions in diamond and other deep-seated minerals. The question of carbonate stability versus the presumably reduced nature of the deep Earth's mantle provides significant impact on the further study of material transport and deep volatile cycle through the history of our planet.

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Structures and Crystal Chemistry of Carbonate at Earth's Mantle Conditions

Merlini

Milani

Maurice

2020

Geophysical Monograph Series

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We report an overview of the crystal structures of carbonates determined ab-initio with X-ray single crystal diffraction techniques at mantle conditions. The determined crystal structures of high-pressure polymorphs of CaCO 3 have revealed that structures denser than aragonite can exist at upper and lower mantle pressures. These results have stimulated the computational and experimental research of thermodynamically stable polymorphs. At lower mantle conditions, the carbonates transform into new structures featuring tetrahedrally coordinated carbon. The identification of a systematic class of carbonates, nesocarbonates, cyclocarbonates, and inocarbonates reveals a complex crystal chemistry, with analogies to silicates. They provide fundamental input for the understanding of deep carbonatite melt physical properties. The possible polymerization of carbonate units will affect viscosity, and the reduced polymerization in crystal structures as a function of oxidation state could suggest that also oxidation state may affect the mobility of deep carbonatitic magmas. Finally, we report two high-pressure structures of mixed alkali carbonates, which reveal that these compounds may form wide solid solutions and incorporate a sensible amount of vacancies, which would allow incorporation of high-strength elements and therefore play an important role for geochemical element partitioning in the mantle.

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Structural evolution of calcite at high temperatures: Phase V unveiled

Cited by 67 publications

References 13 publications

Calcite V: a hundred-year-old mystery has been solved

Calcite V: a hundred-year-old mystery has been solved

Phase Diagrams of Carbonate Materials at High Pressures, with Implications for Melting and Carbon Cycling in the Deep Earth

Structures and Crystal Chemistry of Carbonate at Earth's Mantle Conditions

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