Determining the Kinetics of As₄O₆·2H₂ Formation at High Pressures

Author(s)

Piotr A. Guńka, Kamil F. Dziubek, Francesco Capitani

Abstract

The first quantitative determinations of heterogeneous two-component reaction rates in single crystals under high pressure are reported. The rate of arsenolite inclusion compound with hydrogen, As₄O₆·2H₂, formation on the surface of an arsenolite single crystal has been determined at 1.47 (5) and 1.37 (5) GPa via synchrotron Fourier transform infrared spectroscopy. A thin plate of arsenolite has been completely transformed into the inclusion compound within 1 and 11 h, respectively. The inclusion compound growth rate was found to be linear with a slope of 7.7 (4) μm/h at 1.47 (5) GPa, indicating that reaction at the As₄O₆/As₄O₆·2H₂ phase boundary is rate-limiting. The kinetics of As₄O₆·2H₂ growth at 1.37 (5) GPa exhibits two domains of linear growth with slopes of 0.25 (1) and 1.2 (1) μm/h. Incidentally, a method of growing thin plates of As₄O₆ single crystals via spatial confinement is presented. This work shows that the single-crystal study of two-component reaction kinetics in diamond anvil cells is possible and presents one of the feasible ways to do it in a quantitative manner.

Organisation(s)

Department of Mineralogy and Crystallography

External organisation(s)

Warsaw University of Technology, European Laboratory for Non-Linear Spectroscopy (LENS), Synchrotron SOLEIL, IRFU CEA-Saclay laboratory

Journal

Journal of Physical Chemistry C

Volume

127

Pages

15871-15875

No. of pages

5

ISSN

1932-7447

DOI

https://doi.org/10.1021/acs.jpcc.3c04426

Publication date

08-2023

Peer reviewed

Yes

Austrian Fields of Science 2012

105113 Crystallography, 105116 Mineralogy

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials, General Energy, Physical and Theoretical Chemistry, Surfaces, Coatings and Films

Portal url

https://ucrisportal.univie.ac.at/en/publications/913f1a1e-16ca-4aef-9fec-7088a318f33a