Epitaxy of Calcite on Mica

• Published in: Crystal growth & design Vol. 10; no. 2; pp. 734 - 738
• Main Authors: Stephens, Christopher J, Mouhamad, Youmna, Meldrum, Fiona C, Christenson, Hugo K
• Format: Journal Article
• Language: English
• Published: Washington,DC American Chemical Society 03.02.2010
• Subjects: Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; General studies of phase transitions; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Nucleation; Physics; Theory and models of film growth; Crystallites; Epitaxial layers; Nucleation; Calcium; Epitaxy; Calcium carbonate; Humidity; Growth mechanism; Cleavage; Calcite; Mica
• DOI: 10.1021/cg901130a
• ISSN: 1528-7483

We report for the first time the conditions under which oriented overgrowth of calcite occurs on muscovite mica. Calcite grows in a (001) orientation parallel to the basal cleavage plane on mica surfaces that have been weathered at ambient humidity (35−40%) for periods of at least 1 h, but no epitaxy is found on freshly cleaved mica. Nanometer-thin K2CO3 crystallites are known to form on mica surfaces weathered in this manner, and our experiments show that the presence of these crystallites during the initial stages of nucleation and growth is necessary for the epitaxial growth of calcite. Calcium ions do not adsorb to mica surfaces at the solution concentrations (≤20 mM) used in these experiments, and we suggest that the crystallites provide patches on the surface where the local concentration of both carbonate and calcium ions is high enough to promote epitaxy.