Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Catalli, K. Articles by Williams, Q. Search for Related Content GeoRef GeoRef Citation

A high-pressure phase transition of calcite-III

Department of Earth Sciences, University of California, Santa Cruz, 1156 High Street, Santa Cruz, California 95064, U.S.A.

We document the presence of a high pressure phase transition in metastable calcite-III using infrared spectroscopy. The post-calcite-III transition initiates at a pressure of 15.5 (±2) GPa, and is completed between 25 and 30 GPa. The transition is particularly apparent in the ₄-in-plane bending vibration of the carbonate group, in which two new peaks progressively supplant the doublet associated with calcite-III. Additionally, both the ₃-asymmetric and ₁-symmetric stretches of the carbonate group in the high-pressure phase occur at substantially lower frequencies than the extrapolated positions of the corresponding calcite-III peaks. The geometry of the carbonate unit within the high-pressure phase is likely closer to trigonal symmetry than in the calcite-III structure, and the C-O bond is probably longer than in the lower pressure calcite-III phase.