Elastic properties of heterodesmic composite structures: The case of calcite CaCO3 (space group <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"><mml:mrow><mml:mi>R</mml:mi><mml:mover><mml:mrow><mml:mn>3</mml:mn></mml:mrow><mml:mo stretchy="true">¯</mml:mo></mml:mover><mml:mi>c</mml:mi></mml:mrow></mml:math>)

Ulian, Gianfranco; Moro, Daniele; Valdrè, Giovanni

doi:10.1016/j.jcomc.2021.100184

Cited by 5 publications

(4 citation statements)

References 51 publications

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“…The upgrade of the Hessian matrix was performed by means of the well-known BFGS algorithm [45][46][47][48][49]. For the optimization of both the equilibrium (0 GPa) and hydrostatically compressed/expanded unit cell, the tolerances for the maximum allowed gradient and the maximum atomic displacement for considering the geometry as converged have been set to 1 × 10 −5 hartree bohr −1 and 4 × 10 −5 bohr, respectively [50,51].…”

Section: Methodsmentioning

confidence: 99%

“…where the indices v,u run from 1 to 6 (1 = xx, 2 = yy, 3 = zz, 4 = yz, 5 = xz and 6 = xy), σ v and η u are the components of the stress and pure strain second-rank tensors. The interested reader can find more information on the theory [53], implementation in the CRYSTAL code [52,54] and recent applications [36,37,51,55] in dedicated literature. Singlecrystal elastic properties, namely Young's modulus (E), linear compressibility (β), shear modulus (µ) and Poisson's ratio (υ) were calculated from the elastic moduli using the QUANTAS code [56], with well-known directional relations [34,53,55,57,58].…”

Section: Methodsmentioning

confidence: 99%

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Structural and Elastic Behaviour of Sodalite Na8(Al6Si6O24)Cl2 at High-Pressure by First-Principle Simulations

Ulian

Valdrè

2022

Minerals

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Sodalite Na8(Al6Si6O24)Cl2 (space group P4¯3n) is an important mineral belonging to the zeolite group, with several and manyfold fundamental and technological applications. Despite the interest in this mineral from different disciplines, very little is known regarding its high-pressure elastic properties. The present study aims at filling this knowledge gap, reporting the equation of state and the elastic moduli of sodalite calculated in a wide pressure range, from −6 GPa to 22 GPa. The results were obtained from Density Functional Theory simulations carried out with Gaussian-type basis sets and the well-known hybrid functional B3LYP. The DFT-D3 a posteriori correction to include the van der Waals interactions in the physical treatment of the mineral was also applied. The calculated equation of state parameters at 0 GPa and absolute zero (0 K), i.e., K0 = 70.15(7) GPa, K’ = 4.46(2) and V0 = 676.85(3) Å3 are in line with the properties derived from the stiffness tensor, and in agreement with the few experimental data reported in the literature. Sodalite was found mechanically unstable when compressed above 15.6 GPa.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Structural and Elastic Behaviour of Sodalite Na8(Al6Si6O24)Cl2 at High-Pressure by First-Principle Simulations

Ulian

Valdrè

2022

Minerals

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“…This negative value indicates that when the crystal is subjected to shear stress in one direction, it tends to contract or expand in the opposite direction. In the literature [41], it is reported that the discrepancy has a significant impact on the single-crystal averages but has no effect on the polycrystalline averages because C 14 is absent from any of the stability conditions. Table 3 demonstrates that the stability criterion and the elastic constants correspond well for rhombohedral crystals of pure and K-doped NaNO 3.…”

Section: Elastic Propertiesmentioning

confidence: 99%

First-principles study on the structural, elastic, electronic, optical and thermophysical properties of NaNO₃ and K-doped NaNO₃

Mehra,

Ahmad,

Agrawal

et al. 2024

Phys. Scr.

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The present work represents the structural, electronic, elastic, and thermophysical properties of pure and K-doped NaNO3 obtained using DFT calculations. The estimated structural properties of NaNO3 correspond well with the existing reported values. Electronic characteristics such as band structure and density of statesof pure and doped NaNO3 are analyzed where the calculated band gaps for pure and K-doped NaNO3 are found to be 3.05 eV and 2.90 eV, respectively. The Berry–phase calculations carried out on both systems showed the existence of ferroelectric polarization, where an enhanced spontaneous polarization value of 36 μC/cm2 for K-doped NaNO3, as compared to 20 μC/cm2 for intrinsic NaNO3. The thermophysical properties such as bulk modulus (B0), Debye temperature (θD), and specific heat capacity (Cv) were calculated over a wide temperature range from 0K to 800 K. The linear optical properties namely the dielectric constant, refractive index, absorption coefficient, extinction coefficient and electron energy loss function are calculated in wide energy range from 0 to 30 eV and discussed in detail.

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“…The compressibility of siderite is considered negligible. The Youngs modulus of calcite was previously obtained both experimentally 38,39 and via simulations [40][41][42] . Reported values vary between 95 and 110 × 10 10 N/m 2 .…”

Section: Sample Namementioning

confidence: 99%

Grain boundary widening controls siderite (FeCO3) replacement of limestone (CaCO3)

Weber

Starchenko

Ilavský

et al. 2023

Sci Rep

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The microstructure of minerals and rocks can significantly alter reaction rates. This study focuses on identifying transport paths in low porosity rocks based on the hypothesis that grain boundary widening accelerates reactions in which one mineral is replaced by another (replacement reaction). We conducted a time series of replacement experiments of three limestones (CaCO3) of different microstructures and solid impurity contents using FeCl2. Reacted solids were analyzed using chemical imaging, small angle X-ray and neutron scattering and Raman spectroscopy. In high porosity limestones replacement is reaction controlled and complete replacement was observed within 2 days. In low porosity limestones that contain 1–2% dolomite impurities and are dominated by grain boundaries, a reaction rim was observed whose width did not change with reaction time. Siderite (FeCO3) nucleation was observed in all parts of the rock cores indicating the percolation of the solution throughout the complete core. Dolomite impurities were identified to act as nucleation sites leading to growth of crystals that exert force on the CaCO3 grains. Widening of grain boundaries beyond what is expected based on dissolution and thermal grain expansion was observed in the low porosity marble containing dolomite impurities. This leads to a self-perpetuating cycle of grain boundary widening and reaction acceleration instead of reaction front propagation.

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Elastic properties of heterodesmic composite structures: The case of calcite CaCO3 (space group R3¯c)

Cited by 5 publications

References 51 publications

Structural and Elastic Behaviour of Sodalite Na8(Al6Si6O24)Cl2 at High-Pressure by First-Principle Simulations

Structural and Elastic Behaviour of Sodalite Na8(Al6Si6O24)Cl2 at High-Pressure by First-Principle Simulations

First-principles study on the structural, elastic, electronic, optical and thermophysical properties of NaNO₃ and K-doped NaNO₃

Grain boundary widening controls siderite (FeCO3) replacement of limestone (CaCO3)

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Elastic properties of heterodesmic composite structures: The case of calcite CaCO3 (space group R3¯c)

Cited by 5 publications

References 51 publications

Structural and Elastic Behaviour of Sodalite Na8(Al6Si6O24)Cl2 at High-Pressure by First-Principle Simulations

Structural and Elastic Behaviour of Sodalite Na8(Al6Si6O24)Cl2 at High-Pressure by First-Principle Simulations

First-principles study on the structural, elastic, electronic, optical and thermophysical properties of NaNO3 and K-doped NaNO3

Grain boundary widening controls siderite (FeCO3) replacement of limestone (CaCO3)

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First-principles study on the structural, elastic, electronic, optical and thermophysical properties of NaNO₃ and K-doped NaNO₃