Pressure-induced hydration of the clay mineral nacrite, Al2Si2O5(OH)4 is, in contrast to its polymorph kaolinite, partially irreversible. At ambient conditions after pressure release, a majority phase with composition Al2Si2O5(OH)42H2O with an intense (002) diffraction peak near d ∼8.4 Å has been found. Both in situ X-ray diffraction and simulations based on the density functional theory point to intercalation of molecules in nominally nonswelling clays and specific geophysical and geochemical conditions.
Bibliographical noteFunding Information:
This work was supported by the Leader Researcher program (NRF-2018R1A3B1052042) of the Korean Ministry of Science and ICT. We also thank the partial supports by NRF-2019K1A3A7A09033395 and NRF-2016K1A4A3914691 grants. Synchrotron experiments were performed at the beamlines 6D at PLS-II, BL10-2 at SSRL, and 22-IR-1 at NSLS-II. This research was partially supported by the Graduate School of YONSEI University Research Scholarship Grants in 2019.
Copyright © 2019 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Geochemistry and Petrology
- Atmospheric Science
- Space and Planetary Science