Compare the Difference Between Similar Terms

Difference Between

Home / Science & Nature / Science / Chemistry / Organic Chemistry / Difference Between Optical and Geometrical Isomerism

Difference Between Optical and Geometrical Isomerism

February 13, 2020 Posted by Madhu

The key difference between optical and geometrical isomerism is that optical isomers are pairs of compounds which appear as mirror images of each other whereas geometrical isomers are pairs of compounds containing the same substituents attached to a carbon-carbon double bond differently.

Optical isomers and geometrical isomers are two types of stereoisomers. Stereoisomers are organic compounds containing the same molecular formula, but a different spatial arrangement of the atoms. The sequence of chemical bonds is also the same for these isomers.

CONTENTS

1. Overview and Key Difference
2. What is Optical Isomerism
3. What is Geometrical Isomerism
4. Side by Side Comparison – Optical vs Geometrical Isomerism in Tabular Form
5. Summary

What is Optical Isomerism?

Optical isomers are stereoisomers that have the same chemical formula and the same connectivity of atoms but a different spatial arrangement. They come in pairs and are related to each other by reflection. This means these compounds appear as mirror images of each other. These mirror images are non-superposable. Human hands are analogous to this type of isomers.

Difference Between Optical and Geometrical Isomerism

Figure 01: Optical Isomerism result in Mirror Images

The optical isomers of the same compound have similar physical properties except for the property of rotation of plane-polarized light. Here, one isomer rotates the plane-polarized light into one direction while its optical isomer rotates the same plane-polarized light beam to the opposite direction. Therefore, optical isomers can show different biological effects on the same biological system as well.

What is Geometrical Isomerism?

Geometrical isomers are stereoisomers that have the same substituents attached differently to a carbon-carbon double bond. This type of isomers occurs because the double bond between carbon atoms avoid the ability to rotate around the axis of the double bond and this, in turn, gives fixed positions to the isomer. However, in order to be named as a geometrical isomer, the compound should have different substituents attached to both sides of the double bond. If one side of the double bond has the same substituents attached to the carbon atom in that side, then there cannot be a geometrical isomer to that compound.

Key Difference - Optical vs Geometrical Isomerism

Figure 02: Geometrical Isomerism in Stilbene

Geometrical isomers are also called cis-trans isomers because these isomers come in pairs, and we name them as cis-isomer and trans-isomer, considering the relative positions of the substituents. Cis-isomers have similar substituents on the same side while trans-isomers have different substituents on one side.

What is the Difference Between Optical and Geometrical Isomerism?

Optical isomers and geometrical isomers are two types of stereoisomers. The key difference between optical and geometrical isomerism is that optical isomers are pairs of compounds which appear as mirror images of each other, whereas geometrical isomers are pairs of compounds containing the same substituents attached to a carbon-carbon double bond differently. Thus, optical isomers are non-superposable mirror images, whereas geometrical isomers have a difference in the connectivity of substituents to the double bond.

Moreover, another difference between optical and geometrical isomerism is that optical isomers have similar physical properties, but geometrical isomers have different physical properties.

Difference Between Optical and Geometrical Isomerism in Tabular Form

Summary – Optical vs Geometrical Isomerism

Stereoisomers are organic compounds containing the same molecular formula but a different spatial arrangement of the atoms. Optical isomers and geometrical isomers are two types of stereoisomers. The key difference between optical and geometrical isomerism is that optical isomers are pairs of compounds which appear as mirror images of each other, whereas geometrical isomers are pairs of compounds containing the same substituents attached to a carbon-carbon double bond differently.

Reference:

1. “Optical Isomerism in Organic Molecules.” Chemistry LibreTexts, Libretexts, 5 June 2019, Available here.

Image Courtesy:

1. “Énantiomères octaèdriques” By Tpa2067 – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Cis-trans-stilbene” By Pancrat – Own work (CC BY-SA 3.0) via Commons Wikimedia

Related posts:

Difference Between Aldehyde and FormaldehydeDifference Between Aldehyde and Formaldehyde Difference Between Ether and Petroleum EtherDifference Between Ether and Petroleum Ether Difference Between Ester and EtherDifference Between Ester and Ether Difference Between Ethanol and IsopropanolDifference Between Ethanol and Isopropanol Difference Between Methyl Acetate and Ethyl AcetateDifference Between Methyl Acetate and Ethyl Acetate

Filed Under: Organic Chemistry

About the Author: Madhu

Madhu is a graduate in Biological Sciences with BSc (Honours) Degree and currently persuing a Masters Degree in Industrial and Environmental Chemistry. With a mind rooted firmly to basic principals of chemistry and passion for ever evolving field of industrial chemistry, she is keenly interested to be a true companion for those who seek knowledge in the subject of chemistry.

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Request Article

Featured Posts

Difference Between Coronavirus and Cold Symptoms

Difference Between Coronavirus and Cold Symptoms

Difference Between Coronavirus and SARS

Difference Between Coronavirus and SARS

Difference Between Coronavirus and Influenza

Difference Between Coronavirus and Influenza

Difference Between Coronavirus and Covid 19

Difference Between Coronavirus and Covid 19

You May Like

What is the Difference Between C-reactive Protein and Creatinine

What is the Difference Between C-reactive Protein and Creatinine

Difference Between Chamilia Beads and Pandora / Troll Beads

Difference Between Chamilia Beads and Pandora / Troll Beads

Difference Between Active FTP and Passive FTP

Difference Between Active FTP and Passive FTP

Difference Between Enteral and Parenteral

Difference Between Metal Film and Carbon Film Resistors

Difference Between Metal Film and Carbon Film Resistors

Latest Posts

  • What is the Difference Between Corpus Callosum and Corpus Luteum
  • What is the Difference Between Ciprofloxacin and Amoxicillin
  • What is the Difference Between HER2 Positive and HER2 Negative
  • What is the Difference Between Hiatal Hernia and Gallbladder Pain
  • What is the Difference Between SNP and RFLP
  • What is the Difference Between Macrolides and Tetracyclines
  • Home
  • Vacancies
  • About
  • Request Article
  • Contact Us

Copyright © 2010-2018 Difference Between. All rights reserved. Terms of Use and Privacy Policy: Legal.