• journal_title：American Mineralogist
• Contributor：Michael E. Fleet ; Xi Liu
• Publisher：Mineralogical Society of America
• Date：2007-
• Format：text/html
• Language：en
• Identifier：10.2138/am.2007.2716
• journal_abbrev：American Mineralogist
• issn：0003-004X
• volume：92
• issue：10
• firstpage：1764
• section：Letters

The hydrogen-carbonate ion [(HCO₃)⁻] has been detected by Fourier transform infrared (FTIR) spectroscopy in the c-axis structural channel of Na-bearing type A-B carbonate apatite synthesized under conditions of high P (0.1–1 GPa), T (800–1350 °C), and p(CO₂), and accounts for up to one-third of the total complement of channel carbonate. The hydrogen-carbonate ion is only loosely bound in the apatite channel, and breaks down on aging at room temperature. Volatile decomposition products are lost from the carbonate apatite structure, with CO₂ more mobile than H₂O. The mobility of small volatile molecules points to a possible role for the apatite channel in mediating acid-base reactions in restricted surficial environments and biological systems.