How To Determine If A Molecule Is Chiral
Stereochemistry is one of the most challenging topics of the first semester of organic chemistry. The official definition of a chiral molecule is that it is a molecule whose mirror image is not superimposable. However, for those of us who have a hard time rotating 3D molecules in their mind and trying to superimpose them on one another, I came up with an easy step by step chart to help with this task. Let's take a look!
The chart below shows how to determine whether a molecule is chiral or achiral. Please keep in mind that there are exceptions to the chart since there are molecules that do not have stereogenic centers/carbons and are still chiral but these are much more rare.
1. First we need to determine if the molecule has any stereogenic carbons (chiral carbons). These are carbons that are connected to four different groups. If no, the molecule is achiral. If yes, we go to the next question
2. Are there 2 or more stereogenic carbons? If no, the molecule is chiral. If yes, another question
3. Is there a line of symmetry that cuts the molecule in half with two identical halfs. The line of symmetry can be vertical, diagonal, horizontal, etc If yes, the molecule is called MESO and is achiral. If no, the molecule is chiral
How to determine if the molecule is chiral