XeF2

XeF2
Andif1 · CC BY-SA 3.0 · source
Name	Xenon difluoride
IUPACName	Xenon(II) fluoride
OtherNames	XeF2
Formula	XeF2
MolarMass	207.29 g·mol−1
Appearance	colorless crystalline solid
MeltingPoint	129 °C
BoilingPoint	decomposes
Density	4.09 g·cm−3

XeF2 XeF2 is a colorless crystalline inorganic compound of xenon and fluorine that exemplifies noble gas chemistry and expanded valence concepts. First synthesized after the breakthroughs in inert gas reactivity in the 1960s, it is noted for its role in synthetic fluorination, solid-state studies, and demonstrations of hypervalency. XeF2 has been investigated across laboratory studies at institutions such as Harvard University, Massachusetts Institute of Technology, University of Cambridge, University of California, Berkeley, and industrial research at DuPont and 3M.

Introduction

XeF2 was discovered in the wake of landmark reports that transformed understanding of noble gases following the work leading to the Nobel Prize in Chemistry. Early research groups including those at University of California, Berkeley and Imperial College London published experimental evidence for compounds of xenon with fluorine and other elements, shifting paradigms set by figures like Dmitri Mendeleev and revising predictions from the Periodic Table era. The compound's existence influenced theoretical chemistry developments at centers such as California Institute of Technology and Princeton University and motivated spectroscopic campaigns at facilities including National Institute of Standards and Technology and Lawrence Berkeley National Laboratory.

Synthesis and Preparation

XeF2 is commonly prepared by direct fluorination protocols performed in specialized facilities such as those used by researchers at DuPont and 3M. Historical synthetic methods employed controlled reaction of xenon gas with fluorine gas using reactors developed at Bell Labs and refined at Los Alamos National Laboratory under strict containment standards exemplified by procedures in publications from University of Chicago groups. Alternative routes include oxidative fluorination techniques influenced by work at BASF and photochemical methods tested at Max Planck Society laboratories. Scale-up and handling draw on engineering practices from General Electric and chemical safety guidelines from Occupational Safety and Health Administration.

Structure and Bonding

Crystallographic studies at Brookhaven National Laboratory and Argonne National Laboratory indicate a linear molecular geometry for XeF2 in the gas phase, consistent with predictions from molecular orbital theory developed at Bell Labs and Cambridge University. Electron density analyses employing methods from Harvard University and computational protocols from Los Alamos National Laboratory model XeF2 with a central xenon atom exhibiting bonding attributes discussed in theoretical frameworks from Paul Dirac-influenced quantum chemistry and later treatments by researchers at ETH Zurich and University of Oxford. The three-center four-electron (3c–4e) model, advanced in texts associated with Linus Pauling and formalized by groups at MIT and Stanford University, is widely invoked to rationalize its linearity and bond order.

Physical and Chemical Properties

Physical characterizations reported by teams at NIST and Lawrence Livermore National Laboratory show XeF2 as a white crystalline solid with a notable sublimation pressure studied by investigators at University of Illinois Urbana–Champaign and Pennsylvania State University. Thermochemical and kinetic parameters measured by researchers at Caltech and Columbia University document its behavior under thermal and photochemical stress; decomposition pathways were examined in work connected to Argonne National Laboratory and Oak Ridge National Laboratory. Chemical reactivity studies from University of Tokyo and Sorbonne University detail XeF2 as a selective fluorinating agent in contexts explored by pharmaceutical teams at Pfizer and agrochemical researchers at Syngenta.

Reactivity and Applications

XeF2 has found application as a mild and selective fluorinating reagent in synthetic campaigns at Harvard Medical School and industrial research at Eli Lilly; it is used for halogenation and oxidative transformations in routes pursued by groups at Scripps Research and Roche. In materials science, lithography and microfabrication groups at IBM and Intel exploit XeF2 for isotropic silicon etching, leveraging expertise from Bell Labs and fabrication facilities at Semiconductor Research Corporation. Surface science studies at Argonne National Laboratory and sensor development at Sandia National Laboratories have used XeF2 for controlled fluorination procedures. Academic investigations at University of California, Los Angeles and University of Michigan examine its role in probing oxidation states and generating xenon-containing complexes in collaborations with American Chemical Society-affiliated researchers.

Safety and Handling

Handling protocols for XeF2 follow containment principles developed by OSHA and emergency response frameworks used by Federal Emergency Management Agency. Storage and transport practices align with standards from Department of Transportation guidelines and inventory controls modeled after chemical safety systems at University of Cambridge and Imperial College London. Laboratories working with XeF2 employ engineered controls and personal protective equipment similar to recommendations promulgated by Centers for Disease Control and Prevention and hazardous materials teams at Johns Hopkins University Hospital.

Spectroscopy and Characterization

Spectroscopic characterization of XeF2 has been performed using infrared and Raman facilities at NIST and synchrotron sources at SLAC National Accelerator Laboratory and Diamond Light Source. Nuclear magnetic resonance investigations connected to groups at University of Oxford and ETH Zurich have informed assignments, while electron microscopy work at Oak Ridge National Laboratory and mass spectrometry analyses at Argonne National Laboratory provided corroborative data. Computational spectroscopy studies leveraging resources at Lawrence Berkeley National Laboratory and theoretical groups at University of Cambridge have refined predicted vibrational frequencies and electronic transitions in comparisons published in journals affiliated with the Royal Society of Chemistry and the American Chemical Society.

Category:Inorganic compounds