Refinement of the structure of γ-Ca2SiO4

Czaya, R.

doi:10.1107/s0567740871003030

Cited by 57 publications

(22 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The structural parameters such as lattice constants, molar volumes and nearest-neighbor cation-oxygen distances of CaO, Ca 2 SiO 4 (g-Ca 2 SiO 4 and b-Ca 2 SiO 4 ) and CaSiO 3 (wollastonite and pseudowollastonite) are calculated by MD simulation at 300 K. The calculated structural parameters of CaO, Ca 2 SiO 4 and CaSiO 3 successfully reproduced the measured results [19][20][21][22][23] in Tables 2, 3 and 4.…”

Section: Structural and Thermodynamic Properties For The Calcium Oxidsupporting

confidence: 55%

Molecular Dynamics Simulation of the Thermodynamic and Structural Properties for the CaO-SiO2 System

Seo

Tsukihashi

2004

ISIJ International

View full text Add to dashboard Cite

The thermodynamic, structural and transport properties for the CaO-SiO 2 system were calculated by molecular dynamics (MD) simulation using the pairwise potential model with partial ionic charges. The interatomic potential parameters were determined by fitting the physicochemical properties of calcium oxide and calcium silicates with experimentally measured results. The calculated structural properties such as the pair distribution functions and the fractions of bonding types (bridging, non-bridging and free oxygen) of oxygen with silicon atoms in CaO-SiO 2 melts were in good agreement with observed results, and also the self-diffusion coefficients of calcium, silicon and oxygen ions have been calculated at 1 873 K. The DH M , DS M and DG M for the CaO-SiO 2 system were calculated based on the thermodynamic and structural parameters obtained from MD simulation. The phase diagram for the CaO-SiO 2 system estimated by calculated Gibbs energy of mixing shows good agreement with observed result in the range above 50 mol% CaO and the liquid-liquid immiscibility region in the CaO-SiO 2 system have also been assessed by MD calculation.

show abstract

Section: Structural and Thermodynamic Properties For The Calcium Oxidsupporting

confidence: 55%

Molecular Dynamics Simulation of the Thermodynamic and Structural Properties for the CaO-SiO2 System

Seo

Tsukihashi

2004

ISIJ International

View full text Add to dashboard Cite

show abstract

“…First, the β-and γ-C 2 S bulk structures were optimized, relaxing both the atomic coordinates and lattice parameters. The relaxed unit cell parameters are listed in Table 1, together with the experimental values 30,31 and data from previous simulations. 32,33,35 The relaxed crystal structures are shown in Figure 1.…”

Section: Resultsmentioning

confidence: 99%

Hydration Mechanism of Reactive and Passive Dicalcium Silicate Polymorphs from Molecular Simulations

et al. 2015

View full text Add to dashboard Cite

Belite (C 2 S, CCaO, SSiO 2 ) based cements are promising low-CO 2 substitutes of ordinary Portland cement. The main drawback is their low hydration rates, which makes them unpractical for construction. Yet more disconcerting is the different reactivity between polymorphs of belite: while β-C 2 S reacts slowly with water, γ-C 2 S is almost inert. Due to the demand of improving C 2 S reactivity, in this work we aim to understand the hydration mechanism of belite polymorphs by density functional theory and molecular dynamics simulations methods. We calculated the low-index cleavage energies, and the thermodynamic equilibrium structures were constructed through Wulff shape constructing method. We built the adsorption energy surface (AES) maps and found out the transition state structures for (chemi)sorption of water molecules. Finally molecular dynamics were employed to simulate the reactions taking place during 2 ns at room temperature. We found that water dissociation consists of three steps, rotation, dissociation, and diffusion, with different energy barriers. Considering the AES, DFT energy barriers, and the molecular dynamics simulations, the number of reactive sites is the key aspect that controls hydration; even though water reacts preferentially in γ-C 2 S surfaces over in β-C 2 S in terms of energy, a considerably lower number of reactive points in γ-C 2 S would limit the surface hydration and dissolution.

show abstract

“…4 show the structural parameters and crystal structure data for γ-C 2 S (Czaya 1971). In the crystalline structure of γ-C 2 S, Ca 2+ ions are at six-coordinate positions of hexagonally close-packed O 2-, and the average interatomic distance between Ca-O is 0.2369 nm (Czaya 1971).…”

Section: Mechanisms Of Vaterite Formation Due To Carbonation Of γ-C 2 Smentioning

confidence: 99%

Carbonation of γ-Ca2SiO4 and the Mechanism of Vaterite Formation

Saito

Sakai

Morioka

et al. 2010

ACT

View full text Add to dashboard Cite

The carbonation of γ-Ca 2 SiO 4 (γ-C 2 S) and mechanism of vaterite formation have been investigated by evaluating the crystal structures of both γ-C 2 S and vaterite. The samples used were autoclaved calcium silicate hydrate hardening bodies prepared from Ordinary Portland Cement (OPC), γ-C 2 S and α-quartz and then subjected to accelerated carbonation. The ratio of OPC to γ-C 2 S was varied. Ca 2+ in both γ-C 2 S and vaterite was found to be coordinated to six O 2-. In addition, both γ-C 2 S and vaterite have similar atomic arrangements of O 2-and Ca 2+ and Ca-O bond distances. Therefore, it is proposed that vaterite mainly forms from γ-C 2 S via a topotactic reaction during accelerated carbonation.

show abstract

Refinement of the structure of γ-Ca₂SiO₄

Cited by 57 publications

References 2 publications

Molecular Dynamics Simulation of the Thermodynamic and Structural Properties for the CaO-SiO2 System

Molecular Dynamics Simulation of the Thermodynamic and Structural Properties for the CaO-SiO2 System

Hydration Mechanism of Reactive and Passive Dicalcium Silicate Polymorphs from Molecular Simulations

Carbonation of γ-Ca<sub>2</sub>SiO<sub>4</sub> and the Mechanism of Vaterite Formation

Contact Info

Product

Resources

About