Nucleation of metastable aragonite CaCO 3 in seawater
Predicting the conditions in which a compound adopts a metastable structure when it crystallizes out of solution is an unsolved and fundamental problem in materials synthesis, and one which, if understood and harnessed, could enable the rational design of synthesis pathways toward or away from metas...
Published in: | Proceedings of the National Academy of Sciences |
---|---|
Main Authors: | , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
eScholarship, University of California
2015
|
Subjects: | |
Online Access: | http://www.escholarship.org/uc/item/5h7971wm |
id |
ftcdlib:qt5h7971wm |
---|---|
record_format |
openpolar |
spelling |
ftcdlib:qt5h7971wm 2023-05-15T17:51:39+02:00 Nucleation of metastable aragonite CaCO 3 in seawater Sun, W Jayaraman, S Chen, W Persson, KA Ceder, G 3199 - 3204 2015-03-17 application/pdf http://www.escholarship.org/uc/item/5h7971wm english eng eScholarship, University of California qt5h7971wm http://www.escholarship.org/uc/item/5h7971wm public Sun, W; Jayaraman, S; Chen, W; Persson, KA; & Ceder, G. (2015). Nucleation of metastable aragonite CaCO 3 in seawater. Proceedings of the National Academy of Sciences of the United States of America, 112(11), 3199 - 3204. doi:10.1073/pnas.1423898112. UC Berkeley: Retrieved from: http://www.escholarship.org/uc/item/5h7971wm article 2015 ftcdlib https://doi.org/10.1073/pnas.1423898112 2018-09-28T22:52:03Z Predicting the conditions in which a compound adopts a metastable structure when it crystallizes out of solution is an unsolved and fundamental problem in materials synthesis, and one which, if understood and harnessed, could enable the rational design of synthesis pathways toward or away from metastable structures. Crystallization of metastable phases is particularly accessible via low-temperature solution-based routes, such as chimie douce and hydrothermal synthesis, but although the chemistry of the solution plays a crucial role in governing which polymorph forms, how it does so is poorly understood. Here, we demonstrate an ab initio technique to quantify thermodynamic parameters of surfaces and bulks in equilibrium with an aqueous environment, enabling the calculation of nucleation barriers of competing polymorphs as a function of solution chemistry, thereby predicting the solution conditions governing polymorph selection. We apply this approach to resolve the long-standing "calcite-aragonite problem" - the observation that calcium carbonate precipitates as the metastable aragonite polymorph in marine environments, rather than the stable phase calcite - which is of tremendous relevance to biomineralization, carbon sequestration, paleogeochemistry, and the vulnerability of marine life to ocean acidification. We identify a direct relationship between the calcite surface energy and solution Mg-Ca ion concentrations, showing that the calcite nucleation barrier surpasses that of metastable aragonite in solutions with Mg:Ca ratios consistent with modern seawater, allowing aragonite to dominate the kinetics of nucleation. Our ability to quantify how solution parameters distinguish between polymorphs marks an important step toward the ab initio prediction of materials synthesis pathways in solution. Article in Journal/Newspaper Ocean acidification University of California: eScholarship Proceedings of the National Academy of Sciences 112 11 3199 3204 |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
English |
description |
Predicting the conditions in which a compound adopts a metastable structure when it crystallizes out of solution is an unsolved and fundamental problem in materials synthesis, and one which, if understood and harnessed, could enable the rational design of synthesis pathways toward or away from metastable structures. Crystallization of metastable phases is particularly accessible via low-temperature solution-based routes, such as chimie douce and hydrothermal synthesis, but although the chemistry of the solution plays a crucial role in governing which polymorph forms, how it does so is poorly understood. Here, we demonstrate an ab initio technique to quantify thermodynamic parameters of surfaces and bulks in equilibrium with an aqueous environment, enabling the calculation of nucleation barriers of competing polymorphs as a function of solution chemistry, thereby predicting the solution conditions governing polymorph selection. We apply this approach to resolve the long-standing "calcite-aragonite problem" - the observation that calcium carbonate precipitates as the metastable aragonite polymorph in marine environments, rather than the stable phase calcite - which is of tremendous relevance to biomineralization, carbon sequestration, paleogeochemistry, and the vulnerability of marine life to ocean acidification. We identify a direct relationship between the calcite surface energy and solution Mg-Ca ion concentrations, showing that the calcite nucleation barrier surpasses that of metastable aragonite in solutions with Mg:Ca ratios consistent with modern seawater, allowing aragonite to dominate the kinetics of nucleation. Our ability to quantify how solution parameters distinguish between polymorphs marks an important step toward the ab initio prediction of materials synthesis pathways in solution. |
format |
Article in Journal/Newspaper |
author |
Sun, W Jayaraman, S Chen, W Persson, KA Ceder, G |
spellingShingle |
Sun, W Jayaraman, S Chen, W Persson, KA Ceder, G Nucleation of metastable aragonite CaCO 3 in seawater |
author_facet |
Sun, W Jayaraman, S Chen, W Persson, KA Ceder, G |
author_sort |
Sun, W |
title |
Nucleation of metastable aragonite CaCO 3 in seawater |
title_short |
Nucleation of metastable aragonite CaCO 3 in seawater |
title_full |
Nucleation of metastable aragonite CaCO 3 in seawater |
title_fullStr |
Nucleation of metastable aragonite CaCO 3 in seawater |
title_full_unstemmed |
Nucleation of metastable aragonite CaCO 3 in seawater |
title_sort |
nucleation of metastable aragonite caco 3 in seawater |
publisher |
eScholarship, University of California |
publishDate |
2015 |
url |
http://www.escholarship.org/uc/item/5h7971wm |
op_coverage |
3199 - 3204 |
genre |
Ocean acidification |
genre_facet |
Ocean acidification |
op_source |
Sun, W; Jayaraman, S; Chen, W; Persson, KA; & Ceder, G. (2015). Nucleation of metastable aragonite CaCO 3 in seawater. Proceedings of the National Academy of Sciences of the United States of America, 112(11), 3199 - 3204. doi:10.1073/pnas.1423898112. UC Berkeley: Retrieved from: http://www.escholarship.org/uc/item/5h7971wm |
op_relation |
qt5h7971wm http://www.escholarship.org/uc/item/5h7971wm |
op_rights |
public |
op_doi |
https://doi.org/10.1073/pnas.1423898112 |
container_title |
Proceedings of the National Academy of Sciences |
container_volume |
112 |
container_issue |
11 |
container_start_page |
3199 |
op_container_end_page |
3204 |
_version_ |
1766158862407172096 |