Crystal structure of cerium above 50 kbar

Abstract
Insitu x‐ray data has been obtained on 99.99% pure cerium at 50 and 52 kbar with the use of a Bragg‐Brentano parafocusing x‐ray reflection technique under quasihydrostatic conditions, with a thermal cycling procedure. Our results, based upon 22 experimental diffraction lines, indicate that cerium metal exhibits a definite crystallographic transition from fcc to hcp symmetry at 51±1 kbar with a ?7% volume reduction. Previous results are discussed in light of indexing reliability calculations.