A classical view on nonclassical nucleation

Paul J.M. Smeets, Aaron R. Finney*, Wouter J.E.M. Habraken, Fabio Nudelman, Heiner Friedrich, Jozua Laven, James J. De Yoreo, P. Mark Rodger, Nico A.J.M. Sommerdijk

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

176 Scopus citations

Abstract

Understanding and controlling nucleation is important for many crystallization applications. Calcium carbonate (CaCO3) is often used as a model system to investigate nucleation mechanisms. Despite its great importance in geology, biology, and many industrial applications, CaCO3 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 so-called 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 CaCO3 in dilute aqueous solutions. We propose that a dense liquid phase (containing 4–7 H2O per CaCO3 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 CaCO3 in the form of vaterite, which grows via a net transfer of ions from solution according to z Ca2+ + z CO32− → z CaCO3. 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.

Original languageEnglish (US)
Pages (from-to)E7882-E7890
JournalProceedings of the National Academy of Sciences of the United States of America
Volume114
Issue number38
DOIs
StatePublished - Sep 19 2017
Externally publishedYes

Keywords

  • Calcium carbonate
  • Cryo-electron microscopy
  • Crystal growth
  • Molecular simulation
  • Nucleation

ASJC Scopus subject areas

  • General

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