Pre-nucleation clusters as solute precursors in crystallisation.
Crystallisation is at the heart of various scientific disciplines, but still the understanding of the molecular mechanisms underlying phase separation and the formation of the first solid particles in aqueous solution is rather limited. In this review, classical nucleation theory, as well as established concepts of spinodal decomposition and liquid-liquid demixing, is introduced together with a description of the recently proposed pre-nucleation cluster pathway. The features of pre-nucleation clusters are presented and discussed in relation to recent modifications of the classical and established models for phase separation, together with a review of experimental work and computer simulations on the characteristics of pre-nucleation clusters of calcium phosphate, calcium carbonate, iron(oxy)(hydr)oxide, silica, and also amino acids as an example of small organic molecules. The role of pre-nucleation clusters as solute precursors in the emergence of a new phase is summarized, and the link between the chemical speciation of homogeneous solutions and the process of phase separation via pre-nucleation clusters is highlighted.
Department of Chemistry, Physical Chemistry, University of Konstanz, Universitätsstrasse 10, Box 714, D-78464 Konstanz, Germany. denis.gebauer@uni-konstanz.de.
Denis
D
Gebauer
Matthias
M
Kellermeier
Julian D
JD
Gale
Lennart
L
Bergström
Helmut
H
Cölfen
D000596:Amino Acids / Q000737:chemistry*; D002119:Calcium Carbonate / Q000737:chemistry*; D002130:Calcium Phosphates / Q000737:chemistry*; D003460:Crystallization; D005290:Ferric Compounds / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*
D000596:Amino Acids; D002130:Calcium Phosphates; D005290:Ferric Compounds; C021024:ferric hydroxide; D012822:Silicon Dioxide; C020243:calcium phosphate; D002119:Calcium Carbonate