Two- and three-dimensional extended solids and metallization of compressed XeF2

Area of Science:

• Materials Science
• Solid-State Chemistry
• High-Pressure Physics

Background:

• Pressure induces transformations in molecular solids, leading to extended structures with enhanced electronic conductivity.
• Previous studies show insulator-to-metal and molecular-to-non-molecular transitions in elements like O(2), Xe, I(2), CO(2), and N(2) under pressure.

Purpose of the Study:

• To investigate the high-pressure behavior of xenon difluoride (XeF(2)).
• To discover novel non-molecular phases and metallization in XeF(2) under extreme pressure conditions.

Main Methods:

• High-pressure synthesis and characterization of XeF(2) using diamond anvil cells.
• Analysis of structural and electronic properties through spectroscopy and diffraction techniques.

Main Results:

• XeF(2) transforms into a two-dimensional, graphite-like, hexagonal layered structure of semiconducting XeF(4) at approximately 50 GPa.
• Above 70 GPa, XeF(2) further converts into a three-dimensional, fluorite-like structure of metallic XeF(8).
• These transitions involve the delocalization of lone-pair electrons, leading to sp(3)d(2) and p(3)d(5) hybridization and the fulfillment of the octet rule.

Conclusions:

• XeF(2) undergoes simultaneous molecular-to-non-molecular and insulator-to-metal transitions under high pressure.
• The formation of novel 2D and 3D non-molecular phases of XeF(2) demonstrates unique high-pressure chemistry.
• This research expands the understanding of pressure-induced electronic and structural phase transitions in fluorides.