Proto‐Calcite and Proto‐Vaterite in Amorphous Calcium Carbonates

Gebauer, Denis; Gunawidjaja, Philips N.; Ko, J. Y. Peter; Bacsik, Zoltán; Aziz, Baroz; Liu, Lijia; Hu, Yongfeng; Bergström, Lennart; Tai, Cheuk‐Wai; Sham, Tsun‐Kong; Edén, Mattias; Hedin, Niklas

doi:10.1002/ange.201003220

Cited by 111 publications

(171 citation statements)

References 33 publications

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“…8A). This also contrasts with the earlier assignment of the solubility to different forms of ACC, which-although having similar ion activity products-were not corrected for the influence of ionic strength (17,34). The fact that we still observe an amorphous phase, and considering the above discussion, we propose that the observed objects are vitrified droplets of a DLP, rich in calcium carbonate that forms from the solution through a liquid-liquid phase separation process.…”

Section: Resultscontrasting

confidence: 99%

A classical view on nonclassical nucleation

Smeets

Finney

Habraken

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

196

212

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Understanding and controlling nucleation is important for many crystallization applications. Calcium carbonate (CaCO 3 ) is often used as a model system to investigate nucleation mechanisms. Despite its great importance in geology, biology, and many industrial applications, CaCO 3 nucleation is still a topic of intense discussion, with new pathways for its growth from ions in solution proposed in recent years. These new pathways include the socalled nonclassical nucleation mechanism via the assembly of thermodynamically stable prenucleation clusters, as well as the formation of a dense liquid precursor phase via liquid-liquid phase separation. Here, we present results from a combined experimental and computational investigation on the precipitation of CaCO 3 in dilute aqueous solutions. We propose that a dense liquid phase (containing 4-7 H 2 O per CaCO 3 unit) forms in supersaturated solutions through the association of ions and ion pairs without significant participation of larger ion clusters. This liquid acts as the precursor for the formation of solid CaCO 3 in the form of vaterite, which grows via a net transfer of ions from solution according to z Ca 2+ + z CO 3 2− → z CaCO 3 . The results show that all steps in this process can be explained according to classical concepts of crystal nucleation and growth, and that long-standing physical concepts of nucleation can describe multistep, multiphase growth mechanisms.calcium carbonate | nucleation | crystal growth | cryo-electron microscopy | molecular simulation I n the process of forming a solid phase from a supersaturated solution, nucleation is the key step governing the timescale of the transition. Controlling nucleation is an essential aspect in many crystallization processes, where distinct crystal polymorphism, size, morphology, and other characteristics are required. It is, therefore, important to obtain a fundamental understanding of nucleation mechanisms.More than 150 years ago, a basic theoretical framework, classical nucleation theory (CNT) (1, 2), was developed to describe such nucleation events. CNT describes the formation of nuclei from the dynamic and stochastic association of monomeric units (e.g., ions, atoms, or molecules) that overcome a free-energy barrier at a critical nucleus size and grow out to a mature bulk phase. Calcium carbonate (CaCO 3 ) is a frequently used model system to study nucleation (3-5); however, despite the many years of effort, there are still phenomena associated with CaCO 3 crystal formation where the applicability of classical nucleation concepts have been questioned (6). These include certain microstructures and habits of biominerals formed by organisms (7), or geological mineral deposits with unusual mineralogical and textural patterns (8).Three anhydrous crystalline polymorphs of CaCO 3 are observed in nature: vaterite, aragonite, and calcite in order of increasing thermodynamic stability. In many cases, the precipitation of CaCO 3 from solution is described as a multistep process, with amorphous phases first pr...

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Section: Resultscontrasting

confidence: 99%

A classical view on nonclassical nucleation

Smeets

Finney

Habraken

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

196

212

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“…Interestingly, in a recent titration study carried out at pH 9.00, we could not detect any such destabilizing influence of NaCl on prenucleation clusters and actually observed a decrease in the slope due to activity issues [49]. Although we cannot explain these findings with certainty, one may speculate that distinct proto-structures inherent in the clusters at pH 9.00 and 9.75 [44,50] could account for differing dependencies of their formation constant on the bulk ionic strength.…”

Section: Prenucleation Slopescontrasting

confidence: 62%

“…Again, one may infer that pH-dependent changes in the structure of the clusters cause this difference; that is, aspartate might interact preferably with high-pH clusters, which were shown to exhibit lower binding strength and possibly feature a vaterite-like protostructure [44,50].…”

Section: Prenucleation Slopesmentioning

confidence: 99%

The multiple effects of amino acids on the early stages of calcium carbonate crystallization

Picker¹,

Kellermeier²,

Seto³

et al. 2012

Zeitschrift Für Kristallographie - Crystalline Materials

Self Cite

109

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Abstract. Proteins have found their way into many of Nature's structures due to their structural stability, diversity in function and composition, and ability to be regulated as well as be regulators themselves. In this study, we investigate the constitutive amino acids that make up some of these proteins which are involved in CaCO 3 mineralization -either in nucleation, crystal growth, or inhibition processes. By assaying all 20 amino acids with vapor diffusion and in situ potentiometric titration, we have found specific amino acids having multiple effects on the early stages of CaCO 3 crystallization. These same amino acids have been independently implicated as constituents in liquid-like precursors that form mineralized tissues, processes believed to be key effects of biomineralization proteins in several biological model systems.

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“…Very coarse and very fine soils like gravel and silts respectively also take a much longer time to increase shear wave velocity due to the limited rate of permeability in fine soils and the limited number of particle contacts in the very coarse soils. Calcium carbonate forms three anhydrous polymorphs named as calcite, aragonite and vaterite, three other hydrated crystalline phases named as mono hydrocalcite (CaCO 3 •H 2 O), ikaite (CaCO 3 •6H 2 O), and amorphous calcium carbonate (ACC) with differences in short range order and degree of hydration [93][94][95][96][97]. Rodrigues-Navarro et al explains that the efficiency of bio deposition treatment depends on the type and structure of the precipitated CaCO 3 polymorphs (Vaterite or calcite).…”

Section: Caco 3 Precipitationmentioning

confidence: 99%

Effective Use of Plant-Derived Urease in the Field of Geoenvironmental/ Geotechnical Engineering

Ran¹,

Kawasaki²

2016

J Civil Environ Eng

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Geotechnical and geo-environmental engineering applications currently being explored through bio mineralization process include cementation of sands to improve mechanical properties and hence, to enhance bearing capacity and liquefaction resistance, sequestration of carbon, soil erosion control via surficial stabilization, groundwater flow control and remediation of soil and groundwater impacted by metals and radionuclides. Bio mediated system broadly refers to a chemical reaction series that are managed and controlled through biological activities and byproducts resulting from those reactions alter the properties of material in the system. Bio mediated methods such as microbial induced calcite precipitation (MICP), biofilm formation, biogas generation and biopolymers have been developed by injecting or stimulating microbes. MICP is the most widely explored method. Microbes having urease activity enhance the hydrolysis of urea and it helps to control the pH and to precipitate carbonate. Although it is a widely explored bio mediated method it has some disadvantages.The plant-derived urease may offer many benefits over microbial urease to induce carbonate cementation. Therefore, it is advantageous to explore the knowledge regarding such a technique as an eco-friendly method for different applications in the fields of geoenvironmental/geotechnical Engineering. The main objective of this paper is to provide an overview of the importance of plant-derived urease for different applications in the fields of geoenvironmental/ geotechnical engineering. The information presented in this paper may be important for biotechnologists/geoengineers to have wide ranging updates on the current situation.

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Proto‐Calcite and Proto‐Vaterite in Amorphous Calcium Carbonates

Cited by 111 publications

References 33 publications

A classical view on nonclassical nucleation

A classical view on nonclassical nucleation

The multiple effects of amino acids on the early stages of calcium carbonate crystallization

Effective Use of Plant-Derived Urease in the Field of Geoenvironmental/ Geotechnical Engineering

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