Phenanthrene is a polycyclic aromatic hydrocarbon
Polycyclic aromatic hydrocarbon
Polycyclic aromatic hydrocarbons , also known as poly-aromatic hydrocarbons or polynuclear aromatic hydrocarbons, are potent atmospheric pollutants that consist of fused aromatic rings and do not contain heteroatoms or carry substituents. Naphthalene is the simplest example of a PAH...

 composed of three fused benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....

 rings. The name phenanthrene is a composite of phenyl and anthracene
Anthracene is a solid polycyclic aromatic hydrocarbon consisting of three fused benzene rings. It is a component of coal-tar. Anthracene is used in the production of the red dye alizarin and other dyes...

. In its pure form, it is found in cigarette smoke
Tar (tobacco residue)
Tar is the common name for the resinous partially combusted and healed particulate matter produced by the burning of tobacco and other plant material in the act of smoking. Tar is purportedly the most destructive component in habitual tobacco smoking, accumulating in the smoker's lungs over time...

 and is a known irritant
Irritation or exacerbation, in biology and physiology, is a state of inflammation or painful reaction to allergy or cell-lining damage. A stimulus or agent which induces the state of irritation is an irritant...

, photosensitizing
Photosensitivity in animals
Photosensitivity is an abnormal skin reaction to direct sunlight exposure. It is unrelated to a sunburn. These reactions are due to photosensitization, the accumulation of photosensitive compounds beneath the skin. In some cases, the photodynamic substances come from ingested plants or drugs, after...

 skin to light. Phenanthrene appears as a white powder having blue fluorescence.

The compound with a phenanthrene skeleton and nitrogens at the 4 and 5 positions is known as phenanthroline
Phenanthroline is a heterocyclic organic compound. As a bidentate ligand in coordination chemistry, it forms strong complexes with most metal ions...

Phenanthrene is nearly insoluble in water but is soluble in most organic solvents such as toluene
Toluene, formerly known as toluol, is a clear, water-insoluble liquid with the typical smell of paint thinners. It is a mono-substituted benzene derivative, i.e., one in which a single hydrogen atom from the benzene molecule has been replaced by a univalent group, in this case CH3.It is an aromatic...

, carbon tetrachloride
Carbon tetrachloride
Carbon tetrachloride, also known by many other names is the organic compound with the formula CCl4. It was formerly widely used in fire extinguishers, as a precursor to refrigerants, and as a cleaning agent...

, ether
Ethers are a class of organic compounds that contain an ether group — an oxygen atom connected to two alkyl or aryl groups — of general formula R–O–R'. A typical example is the solvent and anesthetic diethyl ether, commonly referred to simply as "ether"...

, chloroform
Chloroform is an organic compound with formula CHCl3. It is one of the four chloromethanes. The colorless, sweet-smelling, dense liquid is a trihalomethane, and is considered somewhat hazardous...

, acetic acid
Acetic acid
Acetic acid is an organic compound with the chemical formula CH3CO2H . It is a colourless liquid that when undiluted is also called glacial acetic acid. Acetic acid is the main component of vinegar , and has a distinctive sour taste and pungent smell...

 and benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....


A classical phenanthrene synthesis is the Bardhan-Sengupta phenanthrene synthesis.

The first step is an electrophilic aromatic substitution reaction, which is allowed when the diphosphorous pentoxide makes the alcohol a better leaving group.