What is the Difference Between Pure and Hybrid Orbitals

Atomic orbitals are regions of space around an atom where electrons are most likely to be found. They have different shapes and energy levels. Pure and hybrid orbitals are two types of atomic orbitals.

What is the difference between pure and hybrid orbitals? Pure orbitals are original atomic orbitals, while hybrid orbitals are formed through hybridization.

Key Areas Covered

1. What are Pure Orbitals 
      – Definition, Features 
2. What are Hybrid Orbitals 
      – Definition, Features 
3. Similarities Between Pure and Hybrid Orbitals
      – Outline of Common Features
4. Difference Between Pure and Hybrid Orbitals
      – Comparison of Key Differences
5. FAQ: Pure and Hybrid Orbitals
      – Answers to Frequently Asked Questions

Key Terms

Pure Orbitals, Hybrid Orbitals

What are Pure Orbitals

Pure orbitals are mathematical functions that describe the probability of finding an electron in a particular region of space around an atom. These functions are derived from the Schrodinger equation.

Some key characteristics of pure orbitals are as below.

1. Shape – Pure orbitals have distinct shapes, such as the spherical shape of s orbitals, the dumbbell shape of p orbitals, and the clover-leaf shape of d orbitals.
2. Orientation – Pure orbitals can have different orientations in space within a given subshell.
3. Energy – Orbitals within the same subshell have the same energy level, but orbitals in different subshells have different energies.

The types of pure orbitals are s orbitals, p orbitals, d orbitals, and f orbitals. Pure orbitals are important in understanding the atomic structure, predicting chemical properties, and studying quantum mechanics.

What are Hybrid Orbitals

Hybrid orbitals form when atomic orbitals of different shapes and energies mix or hybridize to create new orbitals that are more suitable for bonding. Hybrid orbitals are stronger and more stable. Hybridized orbitals have the correct shape and energy to overlap effectively with other atomic orbitals. This results in optimal bond angles and bond lengths.

Hybrid orbitals are involved in determining the molecular geometry of a molecule. The arrangement of hybrid orbitals determines the shapes of the molecule, such as linear, trigonal planar, and tetrahedral.

The types of hybridization are as follows.

1. sp hybridization – one s orbital and one p orbital combine to form two sp hybrid orbitals. These hybrid orbitals are arranged linearly, giving a linear molecular geometry. Carbon Dioxide and acetylene are good examples of this.
2. sp² hybridization – one s orbital and two p orbitals combine to form three sp² hybrid orbitals. These hybrid orbitals are arranged in a trigonal planar geometry. Moreover, the bond angle between two bonds is 120 degrees. Examples of molecules with sp² hybridization include ethylene and benzene.
3. sp³ hybridization – one s orbital and three p orbitals combine to form four sp³ hybrid orbitals.  These orbitals are arranged in tetrahedral geometry, with bind angles of 109.5 degrees. Examples of molecules with sp³ hybridization include methane and water.

Similarities Between Pure and Hybrid Orbitals

1. The wave function describes pure and hybrid orbitals.
2. Moreover, both orbitals hold electrons.
3. In addition, these orbitals have specific spatial orientations.
4. Both pure and hybrid orbitals have associated energy levels.

Difference Between Pure and Hybrid Orbitals

Definition 

• Pure orbitals are original atomic orbitals, while hybrid orbitals are formed through hybridization.

State

• Pure orbitals exist as they are in the atom, while hybrid orbitals are formed by mixing atomic orbitals.

Shape

• Pure orbitals have specific shapes (spherical, dumbbell, etc.), while hybrid orbitals have unique shapes determined by the combination of atomic orbitals.

Orientation

• Pure orbitals have specific orientations in space, whereas hybrid orbitals have orientations that are often more suitable for bonding.

Number

• Pure orbitals are limited in number (s, p, d, f), whereas hybrid orbitals can be numerous, depending on the combination of atomic orbitals.

Conclusion

Pure orbitals are the fundamental atomic orbitals, such as s, p, d, and f, that exist independently. Hybrid orbitals are formed when pure orbitals combine or hybridize to create new orbitals with unique shapes and energies. Thus, this is the main difference between pure and hybrid orbitals.

FAQ: Pure and Hybrid Orbitals

1. How does a hybrid orbital differ from a pure atomic orbital?

A hybrid orbital is formed by the combination of two or more atomic orbitals, while a pure atomic orbital is a single, uncombined orbital. Hybrid orbitals have different shapes and energies than pure atomic orbitals.

2. What are hybrid orbitals and unhybridized orbitals?

Hybrid orbitals are formed by the mixing of atomic orbitals, while unhybridized orbitals remain unchanged. This mixing leads to new orbitals with different shapes and energies.

3. What are the examples of hybrid orbitals?

1. sp: Formed by mixing one s orbital and one p orbital.
2. sp²: Formed by mixing one s orbital and two p orbitals.
3. sp³: Formed by mixing one s orbital and three p orbitals. 

4. How to determine hybrid orbitals?

To determine hybrid orbitals, count the sigma bonds and lone pairs around the central atom. The total number of these determines the hybridization: 2 = sp, 3 = sp², 4 = sp³.

5. How many hybrid orbitals are there in benzene?

The carbon atoms in benzene are sp2 hybridized, which means that they have one unhybridized p orbital that forms part of the pi system.

Reference:

1. “Orbital hybridisation.” Wikipedia. 

Image Courtesy:

1. “Shapes of hybrid orbitals” By Officer781 – Own work (CC BY-SA 4.0) via Commons Wikimedia