High-Pressure Synthesis and Ambient-Pressure Tem Investigation of Mg-Orthocarbonate

Gavryushkin, Pavel N.; Martirosyan, N. S.; Rashchenko, Sergey V.; Sagatova, Dinara N.; Sagatov, Nursultan E.; Wirth, Richard; Lobanov, Sergey S.; Semerikova, Anna; Fedotenko, Timofey; Litasov, Konstantin D.

doi:10.2139/ssrn.3966096

Cited by 3 publications

(5 citation statements)

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“…Theoretical studies have predicted the formation of sp 3 carbonates at pressures and temperatures much lower than are required for the transformation of conventional carbonates for either oxide- or CO 2 -enriched compounds: i.e., for carbonates which have an oxide:CO 2 ratio other than 1:1. − Some of these predictions have recently been confirmed by the synthesis of the sp 3 carbonates Ca 2 CO 4 - Pnma , Mg 2 CO 4 - P 2 1 / c , Sr 2 CO 4 - Pnma , , and Sr 3 (CO 4 )O- I 4/ mcm , which can be obtained at p ≈ 20 GPa and where Sr 2 CO 4 - Pnma and Sr 3 (CO 4 )O- Pnma can be recovered under ambient conditions. These syntheses have all been conducted by reacting mixtures of an alkaline-earth oxide with the corresponding carbonate: e.g., by reacting CaO with CaCO 3 .…”

Section: Introductionmentioning

confidence: 98%

Novel Calcium sp³ Carbonate CaC₂O₅-I4̅2d May Be a Carbon Host in Earth’s Lower Mantle

König

Spahr

Bayarjargal

et al. 2022

ACS Earth Space Chem.

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CaC2O5-I4̅2d was obtained by reacting CO2 and CaCO3 at lower Earth mantle pressures and temperatures ranging between 34 and 45 GPa and between 2000 and 3000 K, respectively. The crystal structure was solved by single-crystal X-ray diffraction and contains carbon atoms tetrahedrally coordinated by oxygen. The tetrahedral CO4 4– groups form pyramidal [C4O10]4– complex anions by corner sharing. Raman spectroscopy allows an unambiguous identification of this compound, and the experimentally determined spectra are in excellent agreement with Raman spectra obtained from density functional theory calculations. CaC2O5-I4̅2d persists on pressure release down to ∼18 GPa at ambient temperature, where it decomposes into calcite and, presumably, CO2 under ambient conditions. As polymorphs of CaCO3 and CO2 are believed to be present in the vicinity of subducting slabs within Earth’s lower mantle, they would react to give CaC2O5-I4̅2d, which therefore needs to be considered instead of end-member CaCO3 in models of the mantle mineralogy.

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Section: Introductionmentioning

confidence: 98%

Novel Calcium sp³ Carbonate CaC₂O₅-I4̅2d May Be a Carbon Host in Earth’s Lower Mantle

König

Spahr

Bayarjargal

et al. 2022

ACS Earth Space Chem.

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“…Although the previous experimental 4 – 6 and theoretical 7 – 13 studies obtained MgCO 3 - C 2 /m at high temperature and pressure, they did not consider the reaction with MgO, the main mineral of the Earth's lower mantle. The theoretical 14 and experimental 15 results of Gavryushkin et al show that MgCO 3 reacts with MgO to form Mg 2 CO 4 - P 2 1 / c orthocarbonate under the temperature and pressure conditions of the lower mantle. By comparing the high-pressure physical properties of MgCO 3 - C 2 /m and Mg 2 CO 4 - P 2 1 / c , it is found that their seismic anisotropy is quite different, while the equation of state, elastic modulus, density and wave velocity have similar relationship with pressure.…”

Section: Resultsmentioning

confidence: 99%

“…Although the previous experimental 4-6 and theoretical [7][8][9][10][11][12][13] studies obtained MgCO 3 -C2/m at high temperature and pressure, they did not consider the reaction with MgO, the main mineral of the Earth's lower mantle. The theoretical 14 and experimental 15 www.nature.com/scientificreports/ of low-velocity zone near the subducting slab. Therefore, we believe that Mg 2 CO 4 -P2 1 /c may exist in the deep mantle, providing strong evidence for carbon storage in carbonate minerals, which may be the main reason why carbonate rocks cannot be detected in the lower mantle.…”

Section: Seismic Propertiesmentioning

confidence: 99%

“…Recently, Gavryushkin et al used USPEX and AIRSS methods to find that MgCO 3 reacts with MgO to form Mg 2 CO 4 , which has two structures, orthorhombic (space group Pnma) and monoclinic (space group P2 1 /c), and its structure is P2 1 /c when the pressure is higher than 50 GPa 14 . Their experiments later confirmed the existence of Mg 2 CO 4 -P2 1 /c at the temperature and pressure of the Earth's lower mantle 15 . Mg 2 CO 4 -P2 1 /c has 28 atoms, it is isostructural to β-Ca 2 SiO 4 16…”

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confidence: 91%

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Comparative study on high-pressure physical properties of monoclinic MgCO3 and Mg2CO4

Liu

Sun

et al. 2022

Sci Rep

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The physical properties of Mg-carbonate at high temperature and pressure are crucial for understanding the deep carbon cycle. Here, we use first-principles calculations to study the physical properties of MgCO3-C2/m and Mg2CO4-P21/c under high pressure. The research shows that the structure and equation of state of MgCO3-C2/m are in good agreement with the experimental results, and the phase transition pressure of Mg2CO4 from pnma to P21/c structure is 44.66 GPa. By comparing the elastic properties, seismic properties and anisotropy of MgCO3-C2/m and Mg2CO4-P21/c, it is found that the elastic modulus and sound velocity of Mg2CO4-P21/c are smaller than those of MgCO3-C2/m, while the anisotropy is larger than that of MgCO3-C2/m. These results indicate that Mg2CO4-P21/c exists in the deep mantle and may be the main reason why carbonate cannot be detected. The minimum thermal conductivity of MgCO3-C2/m and Mg2CO4-P21/c is the largest in the [010] direction and the smallest in the [001] direction. The thermodynamic properties of MgCO3-C2/m and Mg2CO4-P21/c are predicted using the quasi-harmonic approximation (QHA) method.

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“…Recently, Gavryushkin et al used USPEX and AIRSS methods to find that MgCO 3 reacts with MgO to form Mg 2 CO 4 , which has two structures, tetragonal (space group Pnma) and monoclinic (space group P2 1 /c), and its structure is P2 1 /c when the pressure is higher than 50 GPa 14 . Their experiments later confirmed the existence of Mg 2 CO 4 -P2 1 /c at the temperature and pressure of the Earth's lower mantle 15 . Mg 2 CO 4 -P2 1 /c has 28 atoms, it is isostructural to β-Ca 2 SiO 4 16 , and the atoms at the two positions Mg(1) and Mg(2) are six-coordinated, with octahedral coordination polyhedra.…”

Section: Magnesite (Space Groupmentioning

confidence: 91%

Comparative study on high-pressure physical properties of monoclinic MgCO3 and Mg2CO4

Liu

Sun

et al. 2022

Preprint

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The physical properties of Mg-carbonate at high temperatures and pressure are crucial for understanding the deep carbon cycle. Here, we use first-principles calculations to study the physical properties of MgCO3-C2/m and Mg2CO4-P21/c under high pressure. The research shows that the structure and the equation of state of MgCO3-C2/m are in good agreement with the experimental results, and the phase transition pressure of Mg2CO4 from pnma to P21/c is 44.66 GPa. By comparing the elastic properties, seismic properties, and anisotropy of MgCO3-C2/m and Mg2CO4-P21/c, it is found that the elastic modulus and sound velocity of Mg2CO4-P21/c are smaller than those of MgCO3-C2/m, while the anisotropy is larger than that of MgCO3-C2/m. These results indicate that Mg2CO4-P21/c exists in the deep mantle and may be the main reason why carbonate cannot be detected. The minimum thermal conductivity of MgCO3-C2/m and Mg2CO4-P21/c is the largest in the [010] direction and the smallest in the [001] direction. The thermodynamic properties of MgCO3-C2/m and Mg2CO4-P21/c are predicted using the quasi-harmonic approximation (QHA) method.

show abstract

High-Pressure Synthesis and Ambient-Pressure Tem Investigation of Mg-Orthocarbonate

Cited by 3 publications

References 45 publications

Novel Calcium sp³ Carbonate CaC₂O₅-I4̅2d May Be a Carbon Host in Earth’s Lower Mantle

Novel Calcium sp³ Carbonate CaC₂O₅-I4̅2d May Be a Carbon Host in Earth’s Lower Mantle

Comparative study on high-pressure physical properties of monoclinic MgCO3 and Mg2CO4

Comparative study on high-pressure physical properties of monoclinic MgCO3 and Mg2CO4

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High-Pressure Synthesis and Ambient-Pressure Tem Investigation of Mg-Orthocarbonate

Cited by 3 publications

References 45 publications

Novel Calcium sp3 Carbonate CaC2O5-I4̅2d May Be a Carbon Host in Earth’s Lower Mantle

Novel Calcium sp3 Carbonate CaC2O5-I4̅2d May Be a Carbon Host in Earth’s Lower Mantle

Comparative study on high-pressure physical properties of monoclinic MgCO3 and Mg2CO4

Comparative study on high-pressure physical properties of monoclinic MgCO3 and Mg2CO4

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Novel Calcium sp³ Carbonate CaC₂O₅-I4̅2d May Be a Carbon Host in Earth’s Lower Mantle

Novel Calcium sp³ Carbonate CaC₂O₅-I4̅2d May Be a Carbon Host in Earth’s Lower Mantle