phenanthrene

Phenanthrene is a polycyclic aromatic hydrocarbon (PAH) with the chemical formula C14H10 and a molecular weight of 178.23 g/mol. It consists of three fused benzene rings arranged in an angular, or bent, configuration, making it a structural isomer of anthracene. The molecule is planar and predominantly nonpolar.

In terms of physical properties, phenanthrene appears as a white to pale yellow solid. It has a melting point around 101°C and a boiling point near 340°C. It is insoluble in water but readily soluble in many organic solvents such as benzene, toluene, and chloroform. Its density is approximately 1.18 g/cm3 at room temperature.

Phenanthrene occurs naturally in coal tar and is produced during incomplete combustion of organic matter, including fossil fuels and biomass. It is also found as a environmental contaminant in soil and water due to industrial processes and combustion sources. Commercially, it is obtained from coal tar distillation and, less commonly, from petroleum fractions.

Chemically, phenanthrene participates in reactions typical of PAHs, including electrophilic aromatic substitution and oxidation to quinones. In biological systems, it can be metabolized by cytochrome P450 enzymes to dihydrodiol and other oxidized forms. It serves as a reference material in analytical chemistry and is used in the study of PAH behavior, environmental fate, and toxicity. Safety considerations include its potential health and environmental risks; handling should follow appropriate guidelines to minimize exposure and environmental release.

See also: polycyclic aromatic hydrocarbons, coal tar, benzo[a]pyrene.