What is phenanthrene?

Phenanthrene is a hydrocarbon (it has carbon and hydrogen in its structure) whose physical and chemical properties are studied by organic chemistry. It belongs to the group of so-called aromatic compounds, whose fundamental structural unit is benzene.

Aromatics also include fused polycyclic compounds, made up of several aromatic rings that share a carbon-carbon (CC) bond. Phenanthrene is one of these, it has three fused rings in its structure. It is considered an isomer of anthracene, a compound that has its three rings fused in a linear fashion.

It was isolated from the anthracene oil of coal tar. It is obtained by distillation of wood, vehicle emissions, spills of oil and other sources.

It is in the environment through cigarette smoke, and in steroidal molecules it forms the aromatic base of the chemical structure, as shown in the cholesterol molecule.


Chemical structure

Phenanthrene has a chemical structure made up of three benzene rings fused together through a carbon-carbon bond.

It is considered an aromatic structure because it complies with Hückle’s Law for aromaticity, which says: “A compound is aromatic, if it has 4n + 2 delocalized and conjugated (alternating) pi (π) electrons, with the sigma (σ) electrons of simple links.


When applying Hückel’s law to the structure of phenanthrene and taking into account that n corresponds to the number of benzene rings that the structure has, it turns out that 4n + 2 = 4 (3) +2 = 16 π electrons. These are seen as double bonds in the molecule.

Physical and chemical properties of phenanthrene

  • Density 1180 kg / m³; 1.18 g / cm³
  • Melting point 489.15 K (216 ° C)
  • Boiling point 613.15 K (340 ° C)

The properties of a compound are the characteristics or qualities that allow it to be differentiated from others. The properties that are measured to a compound are the physical properties and the chemical properties.

Although phenanthrene is the isomeric form of anthracene, its properties are very different, giving phenanthrene greater chemical stability due to the angular position of one of its aromatic rings.

Uses / applications of phenanthrene


Opioid drugs can be naturally occurring or derived from phenanthrene. These include morphine, codeine, and thebaine.


The most representative uses of phenanthrene are obtained when it is in an oxidized form; that is, as phenanthrenoquinone. In this way it can be used as dyes, medicines, resins, fungicides and in the inhibition of the polymerization of some processes. 9,10 biphenyldicarboxylic acid is used to make polyester and alkyd resin.

Health effects

Not only phenanthrene, but all polycyclic aromatic hydrocarbons, generally known as PAHs, are toxic and harmful to health. They are found in water, soil and air as a product of combustion, oil spills or as a product of reactions in the industrial environment.

Toxicity increases as their chains with fused benzene rings get larger, although that does not mean that short-chain PAHs are not.

Since benzene, which is the fundamental structural unit of these compounds, its high toxicity and mutagenic activity in living beings is already known.

Naphthalene, called against moths, is used to control pests that attack the fabrics of clothing. Anthracene is a microbicide used in tablet form to counteract bad odors caused by bacteria.

In the case of phenanthrene, it accumulates in the fatty tissues of living beings, producing toxicity when the individual is exposed to the pollutant for long periods.

In addition to these effects, the following may be named:

  • It is fuel.
  • After long periods of exposure to phenanthrene, an individual may develop a cough, respiratory distress, bronchitis, respiratory irritation, and skin irritation.
  • If heated to decomposition, it can cause skin and respiratory tract irritation due to the emission of dense and suffocating fumes.
  • May react with strong oxidants.
  • In case of fire involving this compound, it can be controlled with dry carbon dioxide, halon extinguisher or with water spray.
  • It should be stored in cool places, in airtight containers and away from oxidizing substances.
  • Personal protection material (MMP), covered shoe, long-sleeved apron and gloves should be used.
  • According to the National Institute for Occupational Health and Safety, a half-face mask equipped with anti-fog filters and another specific filter for chemical vapors should be used to handle the compound.
  • In case of eye and / or skin irritation, it is recommended to wash with plenty of water, remove contaminated clothing or accessories and, in very serious cases, refer the patient for medical help.

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