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Updated: Aug 7, 2026

Synthesis and Microdiffraction at Extreme Pressures and Temperatures
Published on: October 7, 2013
High-pressure-induced phase transitions in pentaerythritol: X-ray and Raman studies
Zbigniew A Dreger1, Yogendra M Gupta, Choong-Shik Yoo
1Institute for Shock Physics and Department of Physics, Washington State University, Pullman, Washington 99164-2816, USA. dreger@wsu.edu
Abstract:
The high-pressure response of pentaerythritol crystals has been examined to 10 GPa in diamond-anvil cells using angle-dispersive synchrotron X-ray diffraction and Raman spectroscopy. The results reveal two first-order phase transitions: one at 4.8 GPa from phase I, tetragonal I(), to phase II, orthorhombic Pnn2C2v10, with a small approximately 0.5% volume change, and the other at 7.2 GPa to phase III with an unknown crystal structure. We found that phase I exhibits a large crystallographic anisotropy which rapidly decreases with increasing pressure: the ratio of linear compressibilities between two primary crystal axes decreases from betao= 8.1 at 1 atm to betaP = 2.6 at 4 GPa. We suggest that this apparent decrease in crystal anisotropy is due to the disruption of hydrogen bonding in the (001) plane of phase I and eventually leads to an orthorhombic distortion from a quadrilateral network structure in phase I to a quasi one-dimensional structure in phase II. The crystal structure of phase III exhibits a disordered character, and it is likely a conformational variant of phase II.
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