Compression of ice VII to 500 kbar
Abstract
The isothermal compression of ice VII up to 500 kbar has been measured at 23±2°C by high-pressure X-ray diffraction technique using a diamond-anvil cell. Water transforms to ice VI at 9.3±0.3 kbar, ice VI transforms to ice VII at 20.8±0.5 kbar, and no other phase has been observed up to 500 kbar. The compression data fitted to the Birch equation of state yield K0=240±9 kbar and K' 0=4.5, and the volume for ice VII extrapolated to zero pressure is 0.704±0.003 cm 3/g. No theoretical equations of state for H 2O which satisfy the data are available at present. The index of refraction for ice VII is observed to be the same as ruby at the pressure interval 350-400 kbar, and it becomes greater than ruby above these pressures.
- Publication:
-
Earth and Planetary Science Letters
- Pub Date:
- December 1982
- DOI:
- 10.1016/0012-821X(82)90066-8
- Bibcode:
- 1982E&PSL..61..359L
- Keywords:
-
- Compression Loads;
- Ice;
- Isothermal Processes;
- Phase Transformations;
- Planetary Composition;
- X Ray Diffraction;
- Astronomical Models;
- Equations Of State;
- Refractivity;
- Solid State