Pyrene

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For other uses, see Pyrene (disambiguation).

Pyrene

General
Systematic name	pyrene
Other names	benzo(d,e,f)phenanthrene
Molecular formula	C₁₆H₁₀
SMILES	C12=CC=C3C=CC=C4 C=CC(C2=C34)=CC=C1
Molar mass	202.25 g/mol
Appearance	colorless solid (yellow impurities are often found at trace levels in many samples).
CAS number	[129-00-0]
Properties
Density and phase	1.271 g/ml
Solubility in water	0.135 mg/l
Melting point	145-148 °C (418-421 K)
Boiling point	404 °C (677 K)
Structure
Crystal structure	?
Dipole moment	? D
Hazards
MSDS	External MSDS
Main hazards	irritant
NFPA 704	0 1 0
Flash point	non-flammable
R/S statement	R: 36/37/38-45-53 S: 24/25-26-36
RTECS number	UR2450000
Supplementary data page
Structure and properties	n, ε_r, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Related compounds
Related PAHs	benzopyrene
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Pyrene is a polycyclic aromatic hydrocarbon (PAH) consisting of four fused benzene rings, resulting in a large, flat aromatic system. Pyrene is a colorless solid. It forms during incomplete combustion of organic material and therefore can be isolated from coal tar along with a broad range of related compounds. Animal studies have shown pyrene is toxic to the kidneys and the liver.

Pyrene is used commercially to make dyes, pesticides, pharmaceuticals, and plastics. It is also a valuable molecular probe for fluorescence spectroscopy, having a high quantum yield and lifetime (0.65 and 410 nanosecond, respectively, in ethanol at 293K). Its fluorescence emission spectrum is very sensitive to the solvent's polarity, so pyrene has been used as a probe to determine solvent environments.

Pyrene adopts a dimeric structure, with molecules arranged in sandwiched pairs in order to form lattice units. This results in a high degree of symmetry, belonging to the C2h symmetry group.