XeF4 is the chemical formula of the compound Xenon Tetrafluoride. This chemical compound is formed when xenon reacts with fluorine. Its chemical equation could simply be written as :
Xe + 2F2 ——> XeF4
In this process, elemental fluorine supposedly oxidizes xenon, under some specific conditions of temperature and pressure.
Well, this chemical compound consists of two interesting elements namely, Xenon (Atomic number= 54) and Fluorine (Atomic number= 9).
To make this compound, one part of xenon is mixed with exactly four parts of the element, fluorine. It is further heated at a temperature of 400°C placed inside a nickel container, thereafter allowing it to cool down.
The nickel used in this process does not act as a catalyst. It is used to act as a protective layer when it reacts with fluorine.
Xenon Tetrafluoride is the first binary compound that was discovered among other noble gases. The formation of it is an exothermic process, which releases 251KJ/mol energy.
A crystalline substance that is colorless in nature, is formed when xenon reacts with fluorine.
Various studies regarding neutron diffraction have proved that the structure of the chemical compound is square planar.
The same study is backed up by VSEPR theory, as there are two lone pairs in xenon.
The sublimation of the compound occurs at 115.7°C. XeF4 is stable when subjected to normal pressure and temperature.
However, when it comes in contact with water, it reacts with it and releases xenon gas, molecular oxygen, and xenon fluoride. For this reaction to occur, there has to be slight moisture in the air.
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Lewis Structure
To begin with the Lewis structure of the compound xenon tetrafluoride, it is quite essential to know the meaning of the same.
It is a simplified symbolic representation of the electrons which lie in the valence shell of a molecule.
This is generally helpful in showcasing the arrangement of electrons that lie around an individual atom in the specific molecule.
Dots are used to characterize the electrons and lines are drawn to show the bonds between two atoms.
The structure entails the goal of obtaining an electronic configuration, which also means that it follows the octet rule and fits appropriately to the molecules to form the structure.
However, the geometry within that of the molecules is not explained by the Lewis structure method. Therefore, it might be considered as the simplest theory of an electronic structure.
It also helps one identify the physical and chemical properties of any molecule or its compound.
Drawing Lewis structure of XeF4
Step 1– We need to count the valence electrons of the xenon tetrafluoride molecule with the help of a periodic table.
Step 2– The next step asks us to distribute the valence electrons in the molecule, all around the central atom.
Step 3– In the third step, we shall attempt to fill in the outer shells of every atom.
We know, Xenon Tetrafluoride has 36 valence electrons in total. The valence electrons are subsequently added and checked whether the outer shell is full or not.
There are 8 valence electrons in Xenon and 28 in that of all fluorine atoms, since there are 4 fluorine atoms in the compound.
Therefore, 7*4 shall give us 28; the total valence electrons of XeF4 come to be 8+28 which is 36. Hence, there are 36 valence electrons in the compound XeF4.
Xenon shows the least electronegative property. Thus, it is placed in the center surrounded by all the four fluorine atoms.
The next step entails drawing lines to showcase the bonds which connect xenon and fluorine. The bonds consist of two electrons each.
Now, it can be seen that there are single bonds that are four in number. This means, 8 electrons are consumed out of the 36 that were present.
Therefore, now is the time to place the rest of the electrons along with the atoms.
There shall be six electrons around each fluorine atom. This way 24 out of the 28 fluorine atoms have already taken their space, leaving aside two sets of electrons.
It is an exception to the octet rule, as the four electrons which are left behind will not bond with any other element.
They are, therefore, known as lone-pairs or nonbonding electrons.
Molecular Geometry of XeF4
The geometry of molecules, which is also commonly known as molecular structure, is a 3-D structure of the entire molecule.
It is a useful concept to understand and analyze the reactivity, polarity, color, phase of matter, magnetism, and so on.
The Lewis structure theory does not comprehend the shape of a molecule. Therefore, the use of molecular geometry comes into play to determine the basic shape of the molecules.
The Lewis dot structure shows the unpaired electrons or the lone pairs in the end.
These two pairs of non-bonding electrons are present in such a way that there might be electronic repulsion between them.
Therefore, the VSEPR theory states that there must be minimum repulsion between the electrons. This shall help the compound achieve a stable structure.
It focuses on positions attained by the groups of electrons which lie on the central atom of a molecule.
The positions can appropriately be predicted by visualizing that all the groups of electrons, whether they are bonding or nonbonding pairs of electrons.
A proper Lewis structure needs to be made to arrive at the geometry of a molecule. It helps to figure out the number of bonding and a non-bonding group of electrons.
So, to have a stable structure, the non-bonding electrons are placed in a plane that is perpendicular inside an octahedral setting.
They face opposite to each other, which is at a distance of 180°. It is the sole reason for the square planar shape of xenon tetrafluoride.
Hybridization of XeF4
It is the process where the orbitals of an atom fuse and form a new hybridized orbital to create the geometry of molecules along with distinguishing bonding properties.
It also represents the theory of valence bonds. Quantum mechanics explains the idea of hybridization. The same level atomic orbitals are allowed to take part in the process.
The energy is redistributed to the other orbitals to give equivalent energy to those orbitals. The newly made orbitals are called hybrid orbitals.
It occurs only when the atoms undergo the process of bond formation and not when they are in their gaseous state
Two orbitals of an atom having the same energy level fuse together to form a new kind of an orbital. Here we shall see the hybridization of the compound XeF4.
Xenon Tetrafluoride consists of the central atom xenon, which is the epicenter where the hybridization takes place.
The valence shell of the atom contains 6 electrons in the 5p orbital whereas the 5s orbital entails 2 electrons. There are no electrons present in the f and d orbital of the 5th shell.
The two electrons from the 5p orbital jump up to the 5d orbitals to fill up the vacant spaces. The reason being, they are in the excited state of their orbitals.
The remaining 4 unpaired electrons form the sp3d2 hybridization, which consists of 2 unpaired electrons in the 5p orbital and 2 others in the 5d orbital. A sigma bond is created in the process.
Polarity in XeF4
The molecule XeF4 is a nonpolar molecule.
As the geometrical structure of XeF4 is symmetric ie; square planar. All the dipoles across the Xe-F bond cancel out each other and make net dipole equals zero.
Therefore the uniform charge distribution occurs and no polarization occurs across the XeF4 molecule.
You must read out an article polarity of XeF4 for detailed information.
MO Diagram of XeF4
An MO diagram is a descriptive instrument that is particularly used to explain the formation of chemical bonds in molecules with the help of molecular orbital theory.
When atoms combine with other atoms to make molecules, some of the atomic orbitals adds up to form molecular orbitals which are the same in number.
This method specifically suits diatomic molecules. The MO diagrams help in determining the existence of the molecules.
It also helps to identify the strength between the bonds and the electronic transitions.
In the XeF4 MO diagram, it is quite clear that the structure of the compound is square planar. It has a distance of 1.95 A° between the Xe and F.
This is particularly explained by the valence bond theory, as the two non-bonding electrons from 5p are promoted to the 5d orbital.
After the hybridization takes place, 4 number of half-filled orbitals form covalent bonds with the half-filled 2p orbitals of the fluorine atoms in the structure.
Hence, forming XeF4 molecule, in which there are two lone pairs and four bond pairs.
Conclusion
Xenon Tetrafluoride is a basic molecule, as it doesn’t possess a complex structure. It is a non-polar molecule, which means the dipole moment within the bonds is zero.
The structure is square planar and consists of the non-bonding electrons forming an octahedral shape. In an octahedral shape, the axial positions of the geometry are occupied by the lone pairs to minimize repulsion.
This is the reason for the square planar structure of the compound xenon tetrafluoride. It is a colorless white substance that is crystalline and is used to detect metals that might contaminate rubber made of silicone.
It degrades silicone rubber to identify the impurities that exist within the rubber. It also reacts with silicone to create products made of gases and further leaves metal residue.
