Print this article

Hard x-ray induced synthesis of OF2

corresponding

Michael G. Pravica1*, Yonggang Wang3, Melanie White1, Yuming Xiao2, Paul Chow2
*Corresponding author
1. Department of Physics and Astronomy, University of Nevada Las Vegas and
High Pressure Science and Engineering Center (HiPSEC), Las Vegas, USA
2. High Pressure Collaborative Access Team (HP-CAT),
Advanced Photon Source, Argonne National Laboratory, Argonne, USA
3. Center for High Pressure Science and Technology Advanced Research (HPSTAR), Beijing, China

Abstract

We sought to demonstrate that hard x-rays can initiate a sequence of acatalytic photochemical reactions with the aim of creating molecular mixtures (O2 and F2) and then observe the two species react to form OF2 and with little introduction of heat. Two x-ray Raman scattering (XRS) studies of 1. KBF4 and 2. a mixture of KBF4 + KClO4 pressurized to 3 GPa in a diamond anvil cell (DAC) at ambient temperature at the 16 ID-D undulator beamline at the Advanced Photon Source. The spectrometer collected photons with energy losses around 680 eV near the fluorine K-edge. Fluorine K-edge x-ray Raman spectroscopy demonstrated the clear formation of a new peak near 682 eV energy loss after some 8 hours of irradiation and detection of the KBF4/KClO4 mixture which likely represents OF2 produced from the following reaction: O2+2F2→ 2OF2 following irradiation of the mixture to release O2 and F2 , respectively, from each constituent.


INTRODUCTION

Fluorine is the most electronegative element, and thus, would be an excellent choice as a reactant to drive novel chemistry under extreme conditions (e.g. inside pressurized diamond anvil cells)(1) for industrial purposes and for fundamental chemical/bonding insights. Understanding how this reactive element interacts with other simple molecular reactants such as O2 and its mobility under high pressure would be of great interest from the standpoint of better ascertaining the behavior of simple molecular mixtures under shockwave conditions to aid detonation chemistry which occurs at extreme conditions (high pressure and/or high temperature). As there are fluorine-containing explosives (2) which use the NF2 group as an oxidizing moiety (2, 3) such as 3,3,7,7-tetrakis(difluoramino)octahydro1,5-dinitro-1,5-diazocine (HNFX)(2) and Bis- and Tris-difluoroamino perfluorobutane (3), and as F2 can react explosively with some molecules (e.g. H2), significant insights may also be garnered by the effort of developing fluorine chemistry at extreme conditions.

However, to study fluorine at high pressure, i ...