Hydrogen thermal motion in calcium hydroxide: Ca(OH)<sub>2</sub>

Desgranges, Lionel; Grebille, D.; Calvarin, G.; Chevrier, G.; Floquet, N.; Nièpce, J.C.

doi:10.1107/s0108768193003556

Cited by 134 publications

(79 citation statements)

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“…As portlandite is a major component of hydrated cementitious systems and concrete, a change in morphology might modify the durability and may allow the fine tuning of the physical properties of concrete structures. However while the crystal structure of portlandite is well known [1][2][3], not much experimental work has been done to study the growth mechanisms. Work from Gallucci and Scrivener [4] shows a change in portlandite morphology from large clusters to small dispersed and sometimes hexagonal platelets on addition of gypsum (C$) and tricalcium aluminate (C 3 A).…”

Section: Introductionmentioning

confidence: 99%

Changes in portlandite morphology with solvent composition: Atomistic simulations and experiment

Galmarini

Aimable

Ruffray

et al. 2011

Cement and Concrete Research

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Experimental work has been done to determine changes in the particle shape of portlandite grown in the presence of different ions. To quantify the experimentally observed changes in morphology a new analysis tool was developed, allowing the calculation of the relative surface energies of the crystal facets. The observed morphology in the presence of chlorides and nitrates was facetted particles of a similar shape, the addition of sulfates leads to hexagonal platelet morphology and the addition of silicates leads to the formation of large irregular aggregates. In addition to the experimental work, the surfaces of portlandite were studied with atomistic simulation techniques. The empirical force field used has first been validated. The equilibrium morphology of portlandite in vacuum and in water was then calculated. The results indicate that the presence of water stabilizes the [20.3] surface and changes the morphology. This is consistent with the experimental observation of [20.3] surfaces.

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Section: Introductionmentioning

confidence: 99%

Changes in portlandite morphology with solvent composition: Atomistic simulations and experiment

Galmarini

Aimable

Ruffray

et al. 2011

Cement and Concrete Research

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“…Similarly, the refinements for the structures of periclase (MgO) 53 and brucite (Mg(OH) 2 ) 54 were used in the parametrization of the octahedral magnesium values, portlandite (Ca(OH) 2 ) 55 was used to derive the octahedral calcium values, and Li 2 O 56 was used in the parametrization for octahedral lithium. Partial charges were modified where necessary prior to the parametrization to be consistent with the desired stoichiometry expected for substitutions associated within clay sheets based on a pyrophyllite (AlSi 2 O 5 (OH)) model.…”

Section: Methodsmentioning

confidence: 99%

Molecular Models of Hydroxide, Oxyhydroxide, and Clay Phases and the Development of a General Force Field

2004

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The fate of chemical and radioactive wastes in the environment is related to the ability of natural phases to attenuate and immobilize contaminants through chemical sorption and precipitation processes. Our understanding of these complex processes at the atomic level is provided by a few experimental and analytical methods such as X-ray absorption and NMR spectroscopies. However, due to complexities in the structure and composition of clay and other hydrated minerals, and the inherent uncertainties of the experimental methods, it is important to apply theoretical molecular models for a fundamental atomic-level understanding, interpretation, and prediction of these phenomena. In this effort, we have developed a general force field, CLAYFF, suitable for the simulation of hydrated and multicomponent mineral systems and their interfaces with aqueous solutions. Interatomic potentials were derived from parametrizations incorporating structural and spectroscopic data for a variety of simple hydrated compounds. A flexible SPC-based water model is used to describe the water and hydroxyl behavior. Metal-oxygen interactions are described by a LennardJones function and a Coulombic term with partial charges derived by Mulliken and ESP analysis of DFT results. Bulk structures, relaxed surface structures, and intercalation processes are evaluated and compared to experimental and spectroscopic findings for validation. Our approach differs from most others in that we treat most interatomic interactions as nonbonded. This allows us to effectively use the force field for a wide variety of phases and to properly account for energy and momentum transfer between the fluid phase and the solid, while keeping the number of parameters small enough to allow modeling of relatively large and highly disordered systems. Simulations of clay, hydroxide, and oxyhydroxide phases and their interfaces with aqueous solutions combine energy minimization and molecular dynamics methods to describe the structure and behavior of water, hydroxyl, surface species, and intercalates in these systems. The results obtained to date demonstrate that CLAYFF shows good promise to evolve into a widely adaptable and broadly effective force field for molecular simulations of fluid interfaces with clays and other clay-related phases, as well as other inorganic materials characterized by complex, disordered, and often ill-determined structure and composition.

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“…Data have been collected on a 2D image plate and integrated, after standard calibration and corrections, to obtain I(2θ) data, then analyzed by Rietveld method (FullProf package [7]). Ca(OH) 2 structural refinements have been performed considering the P-3 m1 space group, taking ICSD data as initial values [8]. We have refined zero point, scale factor, cell parameters, bond lengths and angles, Debye Waller factors and preferred orientation parameters.…”

Section: Characterization Of Ca(oh) 2 Nanoparticlesmentioning

confidence: 99%

Synthesis and X-Ray Diffraction Analyses of Calcium Hydroxide Nanoparticles in Aqueous Suspension

Taglieri¹,

Mondelli²,

Daniele³

et al. 2013

AMPC

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Calcium hydroxide nanoparticles in aqueous suspensions (also called nanolime) were successfully employed in Cultural Heritage conservation thanks to the ability of favoring re-adhesion of the pictorial layer on original carbonatic substrates or allowing to a better superficial cohesion and protection of treated stones. In this work, we have synthesized nanolime particles in aqueous suspension by two different methods. The produced particles were characterized in the laboratory, in terms of structural and morphological features, by means of X-Ray diffraction powder (XRD) and by transmission electron microscopy (TEM), respectively. Nanoparticles were crystalline, regularly shaped, hexagonally plated and with side dimensions generally ranging from 300 nm to 30 nm or less. Crystal structure of nanolime particles directly in the aqueous suspension, has been also analyzed by synchrotron diffraction from X-ray synchrotron radiation (SR-XRD); data have been analyzed by means of the Rietveld method and we have investigated the structure of Ca(OH) 2 particles in suspension in terms of cell parameters, atomic coordinates, bond lengths and angles.

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Hydrogen thermal motion in calcium hydroxide: Ca(OH)₂

Cited by 134 publications

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Changes in portlandite morphology with solvent composition: Atomistic simulations and experiment

Changes in portlandite morphology with solvent composition: Atomistic simulations and experiment

Molecular Models of Hydroxide, Oxyhydroxide, and Clay Phases and the Development of a General Force Field

Synthesis and X-Ray Diffraction Analyses of Calcium Hydroxide Nanoparticles in Aqueous Suspension

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Hydrogen thermal motion in calcium hydroxide: Ca(OH)2

Cited by 134 publications

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Changes in portlandite morphology with solvent composition: Atomistic simulations and experiment

Changes in portlandite morphology with solvent composition: Atomistic simulations and experiment

Molecular Models of Hydroxide, Oxyhydroxide, and Clay Phases and the Development of a General Force Field

Synthesis and X-Ray Diffraction Analyses of Calcium Hydroxide Nanoparticles in Aqueous Suspension

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Hydrogen thermal motion in calcium hydroxide: Ca(OH)₂