title: Two- and three-dimensional extended solids and metallization of compressed XeF2.
abstract: The application of pressure, internal or external, transforms molecular solids into extended solids with more itinerant electrons to soften repulsive interatomic interactions in a tight space. Examples include insulator-to-metal transitions in O(2), Xe and I(2), as well as molecular-to-non-molecular transitions in CO(2) and N(2). Here, we present new discoveries of novel two- and three-dimensional extended non-molecular phases of solid XeF(2) and their metallization. At approximately 50 GPa, the transparent linear insulating XeF(2) transforms into a reddish two-dimensional graphite-like hexagonal layered structure of semiconducting XeF(4). Above 70 GPa, it further transforms into a black three-dimensional fluorite-like structure of the first observed metallic XeF(8) polyhedron. These simultaneously occurring molecular-to-non-molecular and insulator-to-metal transitions of XeF(2) arise from the pressure-induced delocalization of non-bonded lone-pair electrons to sp(3)d(2) hybridization in two-dimensional XeF(4) and to p(3)d(5) in three-dimensional XeF(8) through the chemical bonding of all eight valence electrons in Xe and, thereby, fulfilling the octet rule at high pressures.
authors: Institute for Shock Physics and Department of Chemistry, Washington State University, Pullman, Washington 99164, USA.
authors: Minseob
authors: M
authors: Kim
authors: Mathew
authors: M
authors: Debessai
authors: Choong-Shik
authors: CS
authors: Yoo
mesh_terms: D018360:Crystallography, X-Ray; D005459:Fluorides / Q000737:chemistry*; D013059:Spectrum Analysis, Raman; D014978:Xenon / Q000737:chemistry*
chemical_list: D014978:Xenon; C048007:xenon fluoride; D005459:Fluorides