Difference Between Anthracene and Phenanthrene

The key difference between anthracene and phenanthrene is that anthracene is less stable compared to phenanthrene.

Anthracene and phenanthrene are structural isomers. They have the same chemical formula, but the structure of the molecule differs from each other. However, both these compounds contain three benzene rings per molecule.

CONTENTS

1. Overview and Key Difference
2. What is Anthracene
3. What is Phenanthrene 
4. Similarities Between Anthracene and Phenanthrene
5. Side by Side Comparison – Anthracene vs Phenanthrene in Tabular Form
6. Summary

What is Anthracene?

Anthracene is a solid compound that has three fused benzene rings in a straight chain. The chemical formula is C₁₄H₁₀. It appears as a colourless solid, and it has a weak aromatic odour. Furthermore, the chemical structure of anthracene is less stable due to less efficient pi bonding.

The major source of anthracene is coal tar. It has about 1.5% anthracene. Furthermore, the common impurities we can find in anthracene are phenanthrene and carbazole. We can produce this material in a laboratory via cyclodehydration of O-methyl substituted diaryl ketones. Moreover, this compound can undergo photodimerization under UV light. We call this dimer dianthracene.

The major use of anthracene is in the production of red dye alizarin. Additionally, there are some other dyes that we can produce using this compound. Further, it is useful as a scintillator in detectors for high energy protons. Besides, like many other polycyclic aromatic hydrocarbons, anthracene is also present in cigarette smoke.

What is Phenanthrene?

Phenanthrene is a polycyclic aromatic hydrocarbon having three fused benzene rings in a non-linear structure. The name phenanthrene is a combination of phenyl and anthracene. It is a colourless solid and is an irritant.

Moreover, this compound is almost insoluble in water but soluble in less polar solvents such as toluene. We can find this material in its pure form in cigarette smoke. Further, it is useful in making dyes, plastics, pesticides, explosives, drugs, etc.

What are the Similarities Between Anthracene and Phenanthrene?

• Anthracene and phenanthrene are structural isomers.
• Moreover, both these compounds contain three benzene rings per molecule.

What is the Difference Between Anthracene and Phenanthrene?

Anthracene is a solid compound that has three fused benzene rings in a straight chain while phenanthrene is a polycyclic aromatic hydrocarbon having three fused benzene rings in a non-linear structure. The key difference between anthracene and phenanthrene is that anthracene is less stable compared to phenanthrene. In phenanthrene, the stability is due to the efficient pi bonding in it.

Below infographic shows more facts on the difference between anthracene and phenanthrene.

Summary – Anthracene vs Phenanthrene

Basically, anthracene and phenanthrene are structural isomers. The key difference between anthracene and phenanthrene is that anthracene is less stable compared to phenanthrene.

Reference:

1. “Anthracene.” Wikipedia, Wikimedia Foundation, 29 July 2019, Available here.

Image Courtesy:

1. “Anthracene molecule ball” By Jynto (talk) – Own work – created with Discovery Studio Visualizer (CC0) via Commons Wikimedia
2. “Phenanthrene molecule ball” By Jynto (talk) – Own work – created with Discovery Studio Visualizer (CC0) via Commons Wikimedia