Selenium dioxide has the chemical formula SeO2. It’s a one-dimensional polymer chain with selenium and oxygen atoms alternating.
This chemical compound is significant because it is only corrosive to metals when it comes into contact with water. Selenium dioxide combines with water to form selenic acid, which causes most metals to corrode.
In addition, selenium dioxide is released into the soil and water as a result of coal or oil burning and rock weathering. Although selenium is useful to living species in tiny doses, it can cause harmful effects such as malformed embryos and reproductive failure when taken in big levels.
Burning sensations, eye irritation, nausea, headache, and other symptoms of selenium dioxide exposure in humans are common.
There are several ways to make selenium dioxide, but the most common approach is to dehydrate selenous acid.
SeO2 + H2O = H2SeO3
Let’s look at the lewis structure, geometry, and hybridization of this object.
Selenium Dioxide Lewis Structure (SeO2)
It is a visual representation of the behaviour and arrangement of valence electrons within an atom, often known as the Lewis dot structure.
Dots represent valence electrons, whereas lines represent bonds.
The atomic symbols of participating atoms are in the centre of a typical structure, and valence electrons are arranged in pairs surrounding them.
The purpose of this structure is to gain a rough notion of how atoms join together to form a new chemical compound with new chemical properties.
How to Draw the Lewis Structure of Selenium Dioxide in Simple Steps
The Lewis structure starts with figuring out how many valence electrons are already available in a given molecule and how many more are required to reach a stable state. Hence,
Step 1: Determine how many valence electrons are already present in a single molecule of selenium dioxide.
Selenium has six valence electrons, and oxygen has six as well.
Because one selenium dioxide molecule contains two oxygen atoms, the total number of valence electrons already present in the molecule is 18.
Step 2: Determine the amount of valence electrons required to complete the octet of all three selenium dioxide participating atoms.
Each atom requires eight valence electrons to complete its outermost shell, according to the octet rule. As a result, one selenium dioxide molecule requires a total of 24 valence electrons.
According to this law, one selenium dioxide molecule requires only six valence electrons.
Step 3: Locate the selenium dioxide molecule’s centre atom.
The central atom is the atom that is present as a single entity within a molecule. Selenium is the central atom as a result of this feature.
Furthermore, the electronegativity values of selenium and oxygen can be compared to confirm this.
Because it must form the most bonds, the element with the lowest electronegativity value becomes the centre atom.
Under the polarity subheading, this will be examined in greater depth.
Step 4: In a linear structure, write the structure by writing already accessible valence electrons in pairs around each participant atom.
The Lewis structure of the SeO2 molecule is shown below.
Is it possible for Selenium Dioxide to have a different Lewis structure?
No, because each atom in a molecule strives to achieve a stable state, this is not possible.
The formal charge distribution on each participating atom can be used to demonstrate this.
With the help of another Lewis structure of selenium dioxide, we can better understand this.
Only one double bond forms between selenium and the oxygen atom in the diagram below.
Because the formal charge distribution is not equal in this structure, it is unstable and impossible.
Valence Electrons – Nonbonding Valence Electrons – 1/2Bonding Electrons is the formal charge distribution formula.
Let’s see what we can come up with:
O: 6 – 6 – 2/2 = -1
Se: 6 – 2 – 6/2 = +1
O: 6 – 4 – 4/2 = 0
The erroneous Lewis structure of SeO2 is shown below.
When we use the aforementioned formula to compute the formal charge distribution for the proper Lewis structure of selenium dioxide, the total is zero [the schematic of the correct Lewis structure is already provided previously in this article].
O: 6 – 4 – 4/2 = 0
Se: 6 – 2 – 8/2 = 0
O: 6 – 4 – 4/2 = 0
Selenium Dioxide Molecular Geometry
Because of its Lewis structure, most people mistake selenium dioxide’s molecular geometry for linear.
It’s critical to understand that selenium dioxide has a bent geometry due to the double bond and lone pairs of valence electrons on both ends.
The Valence Shell Electron Pair Repulsion (VSEPR) Theory can be used to investigate the behaviour of triatomic selenium dioxide in greater depth.
According to the theory, the existence of equal lone pairs of valence electrons on both ends of a double bond causes a strong repulsion in opposite directions.
The oxygen molecules are pushed downward by this force, resulting in a bent-shaped pyramidal geometry.
The steric number of selenium dioxide, which is 4, can also be used to confirm this structure.
It’s also important to remember that selenium dioxide is a polymer chain, meaning it doesn’t exist as a single molecule.
The existence of a bent structure is further supported by the establishment of a chain. The length of the selenium-oxygen bond is 179pm, while the lengths of the terminal oxygen bonds are 162pm.
Selenium Dioxide Hybridization
In selenium dioxide, hybridization of the central atom is sp3.
It occurs when one 2s orbital is mixed and intermixed with three 2p orbitals, resulting in the production of four new hybrid orbitals with identical energy and properties.
Because selenium dioxide resides in a polymer chain, one of the four orbitals is provided by another selenium dioxide.
Selenium dioxide has a similar molecular orbital structure to sulphur dioxide in the gaseous state, but it exists in the solid form as infinite polymer chains that are not planar.
The molecular orbital diagram of Selenium Dioxide is shown below.
Consider using selenium instead of sulphur.
Hybridization and molecular orbital diagrams are diagrammatic and mathematical representations of orbitals functioning in a specific way during bond formation.
While mixing and intermixing, this uniqueness forms new hybrid orbitals with similar energy but different characteristics.
The development of new compounds with new chemical characteristics is attributed to the new hybrid orbitals.
Selenium Dioxide Polarity
It’s vital to remember that the molecular geometry and chemical properties of monomeric selenium dioxide are the only ones that can be trusted.
Selenium dioxide has a dipole moment of 2.62D, making it a polar molecule despite having an equal formal charge distribution.
Polarity refers to a molecule’s ability to behave as a magnet due to the separation of charges within the molecule, resulting in two distinct positive and negative ends.
With the help of electronegativity values of selenium and oxygen atoms, the polar nature of selenium dioxide may be proven.
The difference between the electronegativity values of the involved atoms must be more than 0.5 for a molecule to be polar in nature.
Selenium has an electronegativity of 2.55 and oxygen has an electronegativity of 3.44, with a difference of 0.89. Selenium dioxide is polar in nature because the electronegativity difference is greater than 0.5.
Selenium Dioxide’s Applications (SeO2)
- It is used to make colourless glass because it can remove iron impurities that give the glass its colour.
- It’s a powerful oxidizer that’s used in the allylic oxidation of alkenes to make allylic alcohols, which then oxidise to form ketones and aldehydes.
- It’s utilised as a bluish-black anti-rust coating on steel to keep it from corroding.
- It’s an important aspect of the photo-processing process.
Selenium Dioxide is a well-known example for those interested in understanding why a double bond forms within a molecule.
The distribution of unequal formal charge in the Lewis structure of selenium dioxide makes it difficult for the structure to have only one double bond.
Furthermore, it is critical to recognise that sp3 hybridization of selenium and the polar character of selenium dioxide only lend credibility to monomeric structures.
Furthermore, any divergence from the ideal state in selenium dioxide is primarily attributable to the polymer chain property of the substance. It’s vital to remember that selenium dioxide is a chain of molecules rather than a single molecule.