100 Nano-Stories: sp² & sp³ Hybridization!
Episode #96: Carbon & Graphene Aerogel Chemistry!
It’s your favorite material science & nanotechnology enthusiast! Today, we will cover the hybridization of sp² and sp³ Orbitals to discuss some properties in Carbon & Graphene Aerogels!
There is no article to prepare you today, reader! Let’s begin today’s topic! 😄
Orbitals & Aerogels! 💡
What Is Hybridization & Atomic Orbitals Anyways? 🔑
Before we explain hybridization, we need to explain the Valence Bond Theory!
Valence Bond Theory is used to describe chemical bonding while applying the rules (and weirdness) of quantum mechanics to describe the overlap of atomic orbitals.
Because of quantum mechanics, the electrons in an atom can behave as both a particle and a wave. If electrons behave like a wave, they can be located in an orbital, and an orbital means a region where you have a high chance of finding the electron (as a particle).
Speaking of orbitals, let’s now introduce the two types of orbitals that can help us undergo sp² and sp³ hybridization!
Sigma & Pi Orbitals! 🔑
Briefly, hybridization is combining two things to make one new thing! You are a hybrid of your mom & dad’s DNA! A mule is a hybrid between a male donkey & a female horse!
There are two types of orbitals in the hybridization of carbon and graphene aerogels: “S” and “P” orbitals.
S orbitals are spherical (kind of like a soccer ball), while P orbitals are dumbbell-shaped. In an S orbital, there are two electrons, and in a P orbital, there is 1 electron.
For a P orbital, specifically, there are 3 different orientations of where the orbital/electron can be located: either on the x-axis, y-axis, or z-axis.
If it helps to picture the orientation of P orbitals, think of a dumbbell on the floor. If the dumbbell is pointing horizontally in your view, it’s on the x-axis. If the dumbbell is pointing vertically in your view, it’s on the y-axis. If the dumbbell is pointing up towards your face in your view, it’s on the z-axis.
Carbon Electron Configuration! 🔑
The initial carbon electron configuration looks like this:
Each “1” inside the boxes means 1 electron. An S “subshell” can hold 2 electrons, and a P “subshell” can hold 6 electrons. A subshell is used to hold orbitals/a certain number of electrons (probability of where electrons can be).
For today’s article ignore the “1s” orbital, since we won’t need it for the hybridization of carbon atoms.
Now, it’s time to hybridize! 💥
sp³ Hybridization + Properties! 🔑
In sp³ hybridized orbitals, one of the electrons from the “2s” orbital will move up and fill the empty “2p(z-axis)” orbital.
When we combine the 2s orbital with all the 2p orbitals, they become hybridized (changed/combined to make something new) to make the 2sp³ orbitals.
Since all of the S and P orbitals were used for hybridization, the orbitals will look something like this:
Reminder: each hybridized orbital contains an electron. These orbitals are known as subshells. Subshells can be defined as “groups” that can hold orbitals/a certain number of electrons (probability of where electrons can be). However, these 4 orbitals mean that 4 atoms can share an electron with these orbitals to form covalent bonds! sp³ hybridization is capable of making 4 covalent bonds!
All the electrons/orbitals are repelling each other evenly at an angle of 109.5° in sp³ hybridization.
Finally, since the orbitals overlap/“bump” head-to-head, they are known as sigma bonds (σ). You can tell if it’s a sigma bond if you can draw a line between the covalent bond and it penetrates both the carbon atom and the additional atom that made the covalent bond.
So what’s a molecule that has sp³ hybridization?
sp² Hybridization + Properties! 🔑
The initial carbon electron configuration looks like this:
As usual, one electron from the 2s orbital will go into the empty 2p(z-axis) orbital.
However, in sp² hybridization, one of the P orbitals will not undergo hybridization (mixture/combination). only the 2s orbital and 2 of the P orbitals will create the degenerate (have the same energy) hybridized orbitals.
Since one of the P orbitals remained unhybridized, the orbitals will look something like this:
The unhybridized P Orbital remains in a dumbbell shape. Reminder: each orbital (hybridized and unhybridized) contains an electron.
All the hybridized orbitals/electrons want to get away from each other as possible, so they repel each other evenly at an angle of 120° in sp² hybridization.
The next thing to point out is that orbitals can create bonds, but there are two rules:
- Hybridized Orbitals in Carbon Atoms will make Sigma bonds (σ).
- Unhybridized Orbitals in Carbon Atoms will make Pi bonds (π).
Both can make covalent bonds, but the shape of the pi bonds will look different than the sigma bonds.
Finally, since the orbitals overlap laterally, they are known as pi bonds (π). You can tell if it’s a pi bond if you can draw a line between the covalent bond but it fails to penetrate both the carbon atom and the additional atom that made the covalent bond.
So what’s a molecule that has sp² hybridization?
Closing Thoughts! 💭
You just learned the chemistry to know the basics of many chemical reactions in carbon and graphene aerogels! Look at you, reader! Big-brain time! 🧠
- sp³ hybridization uses all the 4 valence electrons to become hybridized and become degenerated.
- sp² hybridization uses 3 of the 4 valence electrons to become hybridized, leaving the P (z-axis) orbital unhybridized.
- Hybridized Orbitals make sigma bonds (σ) and Unhybridized Orbitals make pi bonds(π).
- Because the electrons are negatively charged, and as charges repel, they want to get as far away from each other. In sp³ hybridization, the angle between the electrons is 109.5°. In sp² hybridization, the angle between the electrons is 120°.
See you tomorrow to introduce my summer research and development (R&D): Carbon Aerogels! 👋🏽
Sigma Bonds → Head-to-head overlap of atomic orbitals. The symbol for sigma is (σ).
Pi Bonds → Lateral overlap of atomic orbitals. The symbol for pi is (π).
Hybridization → Combining two things to make one new thing.
Valence Electrons → Electrons in the outer shell/last row of an atom.
S Orbital → Contains two electrons and their orbitals are shaped like a soccer ball.
P Orbital → Contains one electron and their orbitals are dumbbell-shaped. They are classified into x-axis, y-axis, and z-axis depending on their orientation.
Subshell → Holds orbitals/a certain number of electrons (probability of where electrons can be). S subshells hold up to 2 electrons, and P subshells hold up to 6 electrons.
Degenerate Orbitals → Orbitals with electrons that contain the same energy as each other.
Orbital → A region where you have a high chance of finding the electron(s).
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