Xenon Difluoride

Introduction

With the chemical formula XeF2, xenon difluoride is a potent fluorinating agent. It is known to be one of the most stable compounds formed with xenon. It is moisture sensitive and can disintegrate in contact with water vapor or even light. Xenon difluoride is a white-colored crystalline solid with a compact structure. Xenon Difluoride is known by specific other names such as Difluoroxenon and Xenon Fluoride.

How does xenon form compounds although it is a noble gas?

Because xenon is an inert gas that does not react, you must be asking yourself this question. Xenon is an inert gas having a stable electronic structure that includes filled outermost orbitals. However, because xenon is a massive element, its innermost electrons shield the outer electrons from the nuclei.

As a result, the nucleus's outer electrons have a reduced force of attraction. Electronegative and more minor-sized compounds target the outer electrons of this electron. As a result, fluorine attracts xenon's electrons, causing them to bind.

Structure and Bonding of XeF2

Structure: In this trigonal bi-pyramid, the electron-bound pairs occupy the peak position, resulting in a linear molecule. Except for the lone pairs, the molecule is linear since the bound pairs hover outside the core Xe atom. XeF2 has a linear structure geometry because it has two bonding pairs and three lone pairs.

Hybridization: The valence electrons in xenon are eight. Two electrons establish sigma bonds with fluorine atoms, leaving the other six electrons as three lone pairs. It depicts sp3d hybridization in the excited state of xenon.

Two hybridizations are required in sp3d – sp2 and pd. pd forms axial bonds, while sp2 forms equatorial bonds. Because there is much resistance between the lone pairs, they eventually wind up with greater bond angles, such as equatorial bonds (120°). As a result, lone xenon pairs are arranged at low points, i.e., the triangle's vertices. At the same time, the fluorine atoms are positioned in an axial position. Hence, XeF2 has a linear form and a trigonal bipyramidal geometry.

Bond angle: The angle F-Xe-F is 180 degrees.
Preparation of Xenon Difluoride
The best way to make XeF2 is to heat a 2:1 molecular proportion of xenon and fluorine in a sealed nickel cylinder at 4000° C. When the mixture was swiftly cooled, a transparent solid XeF2 formed.
Xe + F2 gives XeF2

Another method of xenon preparation is reacting xenon and oxygen difluoride (O2F2) at – 118 ° C as shown below.
Xe + O2F2 gives XeF2

Properties

1. Xenon difluoride is a colorless, crystalline structure with a melting point of 1290 degrees Celsius.
2. It produces hydrogen fluoride and xenon when it interacts with hydrogen.
XeF2 + H2 gives Xe + 2HF
3. Substitution reactions with strong protonic acids are possible.
XeF2 + HX gives FXeX + HF
FXeX + HX gives XeX2 + HF
Here, X can be an acid such as CIO4 – (Perchlorate ion), CF3COO – (Trifluoroacetic Acid), SO3F (Fluorosulfuric Acid), etc.
4. In acidic, neutral, or alkaline solutions, it hydrolyses slowly but thoroughly.
2 XeF2 + 2H2O gives 2Xe + 4HF + O2
2 XeF2 + 4NaOH gives 2Xe + 4NaF + O2 + 2H2O
5. It produces IF by oxidising iodine in the presence of BF3. The reaction can be explained as:
I2 + XeF2 gives 2IF + Xe
6. The Xe atom functions as a powerful oxidant in the redox reaction of XeF2 with I2. XeF2 is an excellent oxidizing agent because the Xe-F bond has the lowest bond energy. The products formed are Iodine Fluoride and Xenon.
7. It is a fluorinating agent that's not too strong. It produces fluorobenzene when it interacts with benzene.
8. It is also a powerful oxidizer.