Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published November 16, 1979 | public
Journal Article

B1-B2 Transition in Calcium Oxide from Shock-Wave and Diamond-Cell Experiments

Abstract

Volume and structural data obtained by shock-wave and diamond-cell techniques demonstrate that calcium oxide transforms from the B1 (sodium chloride type) to the B2 (cesium chloride type) structure at 60 to 70 gigapascals (0.6 to 0.7 megabar) with a volume decrease of 11 percent. The agreement between the shockwave and diamond-cell results independently confirms the ruby-fluorescence pressure scale to about 65 gigapascals. The shock-wave data agree closely with ultrasonic measurements on the B1 phase and also agree satisfactorily with equations of state derived from ab initio calculations. The discovery of this B1-B2 transition is significant in that it allows considerable enrichment of calcium components in the earth's lower mantle, which is consistent with inhomogeneous accretion theories.

Additional Information

© 1979 American Association for the Advancement of Science. Received 21 May 1979. We are very grateful to R. A. Bartels, M. M. Abraham, and Y. Chen for generously providing sample material. We thank R. G. Gordon and J. C. Jamieson for helpful comments and discussions. Work supported by NSF grants EAR 75-15006A01 (California Institute of Technology) and EAR 76-81703 (Carnegie Institution of Washington). This is contribution 3258 from the Division of Geological and Planetary Sciences, California Institute of Technology.

Additional details

Created:
August 19, 2023
Modified:
October 25, 2023