The key difference between naphthalene and anthracene is that the naphthalene structure has two similar rings, whereas the anthracene structure has three similar rings.
Both naphthalene and anthracene are important organic compounds that can be categorized as polycyclic aromatic hydrocarbons.
CONTENTS
1. Overview and Key Difference
2. What is Naphthalene
3. What is Anthracene
4. Naphthalene vs Anthracene in Tabular Form
5. Summary – Naphthalene vs Anthracene
What is Naphthalene?
Naphthalene is an organic compound having the chemical formula C10H8. It is easy to identify this compound as the simplest polycyclic aromatic hydrocarbon compound. Naphthalene can be found as a white crystalline solid that has a characteristic odor similar to coal tar, even at very low concentrations. When considering the structure of naphthalene, it has a fused pair of benzene rings.
A naphthalene molecule tends to occur as a fusion of a pair of benzene rings. This results in the classification of this compound as a benzenoid polycyclic aromatic hydrocarbon or PAH. There are eight carbon atoms that are not shared between the two ring structures. Each of these eight carbon atoms contains one hydrogen atom per carbon atom. In the nomenclature of this naphthalene molecule, the eight carbon atoms are numbered from 1 to 8 in a sequence around the perimeter of the molecule. This numbering starts with the carbon atom that is adjacent to a shared one. Generally, the shared carbon atoms are numbered 4a and 8a.
Naphthalene molecule has a planar structure. However, unlike in the benzene ring, the C-C bonds in this molecule have different lengths. We can find this difference through X-ray diffraction, and it is consistent with the valence bond model in naphthalene.
Naphthalene substance is useful as a precursor to other chemical compounds for the production of phthalic anhydride, many azo dyes, insecticides, and other useful agrochemicals.
What is Anthracene?
Anthracene can be described as a solid compound that has three fused benzene rings in a straight chain. The chemical formula of this compound is C14H10, and it appears as a colorless solid. It also has a weak aromatic odor. Moreover, the chemical structure of anthracene is less stable due to less efficient pi bonding.
The major source of anthracene can be given as coal tar. Coal tar has about 1.5% anthracene. Further, 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 the Difference Between Naphthalene and Anthracene?
The key difference between naphthalene and anthracene is that naphthalene structure has two similar rings, whereas anthracene structure has three similar rings. Naphthalene occurs as white solid crystals or flakes and has a strong odor of coal tar, whereas anthracene occurs as colorless crystals and is weakly aromatic. Moreover, the chemical formula of naphthalene is C10H8, while the chemical formula of anthracene is C14H10.
The below infographic presents the differences between naphthalene and anthracene in tabular form for side-by-side comparison.
Summary – Naphthalene vs Anthracene
Naphthalene is an organic compound having the chemical formula C10H8, while anthracene is an organic compound having the chemical formula C14H10. The key difference between naphthalene and anthracene is that the naphthalene structure has two similar rings, whereas the anthracene structure has three similar rings.
Reference:
1. “Naphthalene.” Encyclopædia Britannica, Encyclopædia Britannica, Inc.
Image Courtesy:
1. “Naphthalene-from-xtal-3D-balls” By Ben Mills – Own work (Public Domain) via Commons Wikimedia
2. “Anthracene molecule ball” By Jynto (talk) – This image was created with Discovery Studio Visualizer. (CC0) via Commons Wikimedia