title: Carbonic acid: an important intermediate in the surface chemistry of calcium carbonate.
abstract: Calcium carbonate is an important and ubiquitous component of biological and geochemical systems. In this study, the surface chemistry of calcium carbonate with several trace atmospheric gases including HNO3, SO2, HCOOH, and CH3COOH is investigated with infrared spectroscopy. Adsorbed carbonic acid, H2CO3, is found to be an intermediate in these reactions. In the absence of adsorbed water, carbonic acid is stable on the surface at room temperature. However, upon water adsorption, carbonic acid dissociates as indicated by the evolution of gaseous CO2 and the disappearance of infrared absorption bands associated with adsorbed carbonic acid. Thus, it is postulated that under ambient conditions, carbonic acid may be an important albeit short-lived intermediate in the surface chemistry of calcium carbonate.
authors.affiliation: Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA.
authors.forename: Hashim A
authors.initials: HA
authors.lastname: Al-Hosney
authors.forename: Vicki H
authors.initials: VH
authors.lastname: Grassian
mesh_terms: D000042:Absorption; D001272:Atmosphere / Q000737:chemistry; D002119:Calcium Carbonate / Q000737:chemistry; D002255:Carbonic Acid / Q000737:chemistry*; D019015:Geologic Sediments / Q000737:chemistry*; D012995:Solubility; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D002255:Carbonic Acid; D002119:Calcium Carbonate