Al-Hosney Hashim A, Grassian Vicki H
Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA.
J Am Chem Soc. 2004 Jul 7;126(26):8068-9. doi: 10.1021/ja0490774.
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.
碳酸钙是生物和地球化学系统中一种重要且普遍存在的成分。在本研究中，利用红外光谱研究了碳酸钙与几种微量大气气体（包括硝酸、二氧化硫、甲酸和乙酸）的表面化学。发现吸附的碳酸（H₂CO₃）是这些反应中的中间体。在没有吸附水的情况下，碳酸在室温下在表面是稳定的。然而，水吸附后，碳酸会分解，表现为气态二氧化碳的逸出以及与吸附碳酸相关的红外吸收带的消失。因此，据推测在环境条件下，碳酸可能是碳酸钙表面化学中一种重要但寿命短暂的中间体。
