scholarly journals A hydrated crystalline calcium carbonate phase: Calcium carbonate hemihydrate

Science ◽  
2019 ◽  
Vol 363 (6425) ◽  
pp. 396-400 ◽  
Author(s):  
Zhaoyong Zou ◽  
Wouter J. E. M. Habraken ◽  
Galina Matveeva ◽  
Anders C. S. Jensen ◽  
Luca Bertinetti ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Cement Industry ◽  
Industrial Processes ◽  
Magnesium Ions ◽  
Monoclinic Structure ◽  
Ambient Conditions ◽  
Amorphous Calcium Carbonate ◽  
Hydrated Crystal ◽  
Global Carbon

As one of the most abundant materials in the world, calcium carbonate, CaCO3, is the main constituent of the skeletons and shells of various marine organisms. It is used in the cement industry and plays a crucial role in the global carbon cycle and formation of sedimentary rocks. For more than a century, only three polymorphs of pure CaCO3—calcite, aragonite, and vaterite—were known to exist at ambient conditions, as well as two hydrated crystal phases, monohydrocalcite (CaCO3·1H2O) and ikaite (CaCO3·6H2O). While investigating the role of magnesium ions in crystallization pathways of amorphous calcium carbonate, we unexpectedly discovered an unknown crystalline phase, hemihydrate CaCO3·½H2O, with monoclinic structure. This discovery may have important implications in biomineralization, geology, and industrial processes based on hydration of CaCO3.

scholarly journals Role of Internal Stress in the Early-Stage Nucleation of Amorphous Calcium Carbonate Gels

2020 ◽  
Vol 10 (12) ◽  
pp. 4359 ◽  
Author(s):  
Qi Zhou ◽  
Tao Du ◽  
Lijie Guo ◽  
Gaurav Sant ◽  
Mathieu Bauchy
Keyword(s):  
Molecular Dynamics ◽  
Calcium Carbonate ◽  
Driving Force ◽  
Early Stage ◽  
Local Stress ◽  
Amorphous Calcium Carbonate ◽  
Local Coordination ◽  
Dynamics Simulations ◽  
Over Time

Although calcium carbonate (CaCO3) precipitation plays an important role in nature, its mechanism remains only partially understood. Further understanding the atomic driving force behind the CaCO3 precipitation could be key to facilitate the capture, immobilization, and utilization of CO2 by mineralization. Here, based on molecular dynamics simulations, we investigate the mechanism of the early-stage nucleation of an amorphous calcium carbonate gel. We show that the gelation reaction manifests itself by the formation of some calcium carbonate clusters that grow over time. Interestingly, we demonstrate that the gelation reaction is driven by the existence of some competing local molecular stresses within the Ca and C precursors, which progressively get released upon gelation. This internal molecular stress is found to originate from the significantly different local coordination environments exhibited by Ca and C atoms. These results highlight the key role played by the local stress acting within the atomic network in governing gelation reactions.

Layered growth of crayfish gastrolith: About the stability of amorphous calcium carbonate and role of additives

2015 ◽  
Vol 189 (1) ◽  
pp. 28-36 ◽  
Author(s):  
Wouter J.E.M. Habraken ◽  
Admir Masic ◽  
Luca Bertinetti ◽  
Ali Al-Sawalmih ◽  
Lilah Glazer ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Amorphous Calcium Carbonate ◽  
Layered Growth ◽  
The Stability

Role of Magnesium Ion in the Stabilization of Biogenic Amorphous Calcium Carbonate: A Structure−Function Investigation

2010 ◽  
Vol 22 (1) ◽  
pp. 161-166 ◽  
Author(s):  
Yael Politi ◽  
David R. Batchelor ◽  
Paul Zaslansky ◽  
Bradley F. Chmelka ◽  
James C. Weaver ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Structure Function ◽  
Magnesium Ion ◽  
Amorphous Calcium Carbonate

scholarly journals Anisotropic nanowire growth via a self-confined amorphous template process: A reconsideration on the role of amorphous calcium carbonate

Nano Research ◽  
2016 ◽  
Vol 9 (5) ◽  
pp. 1334-1345 ◽  
Author(s):  
Li-Bo Mao ◽  
Lei Xue ◽  
Denis Gebauer ◽  
Lei Liu ◽  
Xiao-Fang Yu ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Nanowire Growth ◽  
Amorphous Calcium Carbonate ◽  
Template Process

Effects of Magnesium Ions and Water Molecules on the Structure of Amorphous Calcium Carbonate: A Molecular Dynamics Study

2013 ◽  
Vol 117 (47) ◽  
pp. 14849-14856 ◽  
Author(s):  
Hidekazu Tomono ◽  
Hiroki Nada ◽  
Fangjie Zhu ◽  
Takeshi Sakamoto ◽  
Tatsuya Nishimura ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Calcium Carbonate ◽  
Water Molecules ◽  
Magnesium Ions ◽  
Amorphous Calcium Carbonate

The role of pH and Mg on the stability and crystallization of amorphous calcium carbonate

2012 ◽  
Vol 536 ◽  
pp. S477-S479 ◽  
Author(s):  
J.D. Rodriguez-Blanco ◽  
S. Shaw ◽  
P. Bots ◽  
T. Roncal-Herrero ◽  
L.G. Benning
Keyword(s):  
Calcium Carbonate ◽  
Amorphous Calcium Carbonate ◽  
The Stability

A crucial process: organic matrix and magnesium ion control of amorphous calcium carbonate crystallization on β-chitin film

CrystEngComm ◽  
2015 ◽  
Vol 17 (1) ◽  
pp. 32-39 ◽  
Author(s):  
Yufei Ma ◽  
Qingling Feng
Keyword(s):  
Aqueous Solution ◽  
Calcium Carbonate ◽  
Organic Matrix ◽  
Water Soluble ◽  
Magnesium Ion ◽  
Magnesium Ions ◽  
Amorphous Calcium Carbonate ◽  
Transformation Processes

ACC transformation processes occurring on chitin film mediated by a water soluble matrix or magnesium ions in aqueous solution were investigated.

scholarly journals Role of Impurities in the Kinetic Persistence of Amorphous Calcium Carbonate: A Nanoscopic Dynamics View

2018 ◽  
Vol 122 (29) ◽  
pp. 16983-16991 ◽  
Author(s):  
Ayumi Koishi ◽  
Alejandro Fernandez-Martinez ◽  
Beatrice Ruta ◽  
Monica Jimenez-Ruiz ◽  
Roberta Poloni ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Amorphous Calcium Carbonate

scholarly journals Raman Study on Pompeii Potteries: The Role of Calcium Hydroxide on the Surface Treatment

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Daniele Chiriu ◽  
Pier Carlo Ricci ◽  
Andrea Polcaro ◽  
Paolo Braconi ◽  
David Lanzi ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Temperature ◽  
Calcium Carbonate ◽  
Surface Treatment ◽  
Calcium Hydroxide ◽  
Archaeological Site ◽  
Ambient Conditions ◽  
Cooking Process ◽  
Raman Study

Pottery samples from the Pompeii archaeological site were investigated by IR Raman spectroscopy and EDAX measurements. The analysis of the Raman spectra of the surfaces reveals the presence calcium hydroxide (peak at about 780 cm−1) while the calcium carbonate is totally absent. The comparative studies on the carbonation effect of the surfaces were performed on laboratory grown samples of calcium hydroxide. The samples were treated at high temperature and exposed to different ambient conditions, and the analysis suggests that the original surfaces of Roman pottery were scattered by calcium hydroxide (limewash) before the cooking process in the furnace. The result of this surface treatment not only permits a vitrification of the surfaces but also seems to reduce the content of CO2in the furnace atmosphere and then obtain a more oxidant ambient during the cooking of the pottery. These results give new insights on the real degree of knowledge of the Romans about the art of ceramics and more generally about chemistry and technologies.

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