Article · Wikipedia archive · Last revised Jul 18, 2026

Acenaphthylene

Acenaphthylene, a polycyclic aromatic hydrocarbon is an ortho- and peri-fused tricyclic hydrocarbon. The molecule resembles naphthalene with positions 1 and 8 connected by a -CH=CH- unit. It is a yellow solid. Unlike many polycyclic aromatic hydrocarbons, it has no fluorescence.

Last revised
Jul 18, 2026
Read time
≈ 2 min
Length
539 w
Citations
8
Source
Acenaphthylene
Skeletal formula
source ↗
Space-filling model
source ↗
Names
Preferred IUPAC name
Acenaphthylene1
Other names
Cyclopenta[de]naphthalene
Acenaphthalene
Tricyclo[6.3.1.04,12]dodeca-1(12),2,4,6,8,10-hexaene
Tricyclo[6.3.1.04,12]dodecahexaene
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.005.380
UNII
  • InChI=1S/C12H8/c1-3-9-4-2-6-11-8-7-10(5-1)12(9)11/h1-8H checkY
    Key: HXGDTGSAIMULJN-UHFFFAOYSA-N checkY
  • InChI=1/C12H8/c1-3-9-4-2-6-11-8-7-10(5-1)12(9)11/h1-8H
    Key: HXGDTGSAIMULJN-UHFFFAOYAQ
  • c3cc1cccc2\C=C/c(c12)c3
  • c1cc2cccc3c2c(c1)C=C3
Properties
C12H8
Molar mass 152.196 g·mol−1
Appearance Yellow crystals
Density 0.8987 g cm−3
Melting point 91.8 °C (197.2 °F; 364.9 K)
Boiling point 280 °C (536 °F; 553 K)
Insoluble
Solubility in ethanol very soluble
Solubility in diethyl ether very soluble
Solubility in benzene very soluble
Solubility in chloroform soluble
Thermochemistry[1]2
166.4 J mol−1 K−1
Enthalpy of fusion fHfus)
186.7 kJ/mol
69 kJ/mol
71.06 kJ/mol
Hazards
GHS labelling:
GHS06: ToxicGHS07: Exclamation mark
Danger
H302, H310, H315, H319, H330, H335
P260, P262, P264, P270, P271, P280, P284, P301+P312, P302+P350, P302+P352, P304+P340, P305+P351+P338, P310, P312, P320, P321, P330, P332+P313, P337+P313, P361, P362, P363, P403+P233, P405, P501
Flash point 122 °C (252 °F; 395 K)
Related compounds
Related compounds
acenaphthene
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Acenaphthylene, a polycyclic aromatic hydrocarbon is an ortho- and peri-fused tricyclic hydrocarbon. The molecule resembles naphthalene with positions 1 and 8 connected by a -CH=CH- unit. It is a yellow solid.3 Unlike many polycyclic aromatic hydrocarbons, it has no fluorescence.

Occurrence

Acenaphthylene occurs as about 2% of coal tar. It is produced industrially by gas phase dehydrogenation of acenaphthene.3

Reactions

Hydrogenation gives the more saturated compound acenaphthene. Chemical reduction affords the radical anion sodium or potassium acenaphthalenide, which is used as a strong reductant (E = -2.26 V vs FC).4

It functions as a ligand for some organometallic compounds.5

Uses

Polymerisation of acenaphthylene with acetylene in the presence of a Lewis acid catalyst gives electrically conductive polymers. Acenaphthylene possesses excellent properties as an antioxidant in cross-linked polyethylene and ethylene-propylene rubber. Thermal trimerization of acenaphthylene leads to decacyclene, which can be further processed to sulfur dyes.6

Toxicity

The no-observed-adverse-effect-level of acenaphthylene after repeated 28-day oral administration to both male and female rats was found to be 4 mg/kg/day.7

References

References

  1. Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 210. doi:10.1039/9781849733069-00130. ISBN 978-0-85404-182-4.
  2. John Rumble (June 18, 2018). CRC Handbook of Chemistry and Physics (99th ed.). CRC Press. pp. 5–3. ISBN 978-1138561632.
  3. Griesbaum, Karl; Behr, Arno; Biedenkapp, Dieter; Voges, Heinz-Werner; Garbe, Dorothea; Paetz, Christian; Collin, Gerd; Mayer, Dieter; Höke, Hartmut (2000). "Hydrocarbons". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a13_227. ISBN 3527306730.
  4. Connelly, Neil G.; Geiger, William E. (1996-01-01). "Chemical Redox Agents for Organometallic Chemistry". Chemical Reviews. 96 (2): 877–910. doi:10.1021/cr940053x. ISSN 0009-2665. PMID 11848774.
  5. Motoyama, Yukihiro; Itonaga, Chikara; Ishida, Toshiki; Takasaki, Mikihiro; Nagashima, Hideo (2005). "Catalytic Reduction of Amides to Amines with Hydrosilanes Using a Triruthenium Carbonyl Cluster as the Catalyst". Organic Syntheses. 82: 188. doi:10.15227/orgsyn.082.0188.
  6. Ullmann, 4th ed., 21, 70
  7. Tanabe, S.; et al. (2017). "Toxicity of repeated 28-day oral administration of acenaphthylene in rats". Fundamental Toxicological Sciences. 4 (6): 247–259. doi:10.2131/fts.4.247.