Octane

Octane is an organic compound with the chemical formula C₈H₁₈. It is an alkane with eight carbon atoms. It is commonly used in fuel. It is the most important part of gasoline, because it is the part that lets out most of the energy that comes from gasoline when it is burned. A high octane fuel will be better than a low octane fuel.

Octane
IUPAC name	Octane
Identifiers
CAS number	111-65-9
PubChem	356
EC number	203-892-1
DrugBank	DB02440
KEGG	C01387
MeSH	octane
ChEBI	CHEBI:17590
RTECS number	RG8400000
SMILES	CCCCCCCC
Beilstein Reference	1696875
Gmelin Reference	82412
3DMet	B00281
Properties
Molecular formula	C8H18
Molar mass	114.23 g mol-1
Appearance	Colorless liquid
Odor	Gasoline-like
Density	0.703 g cm−3
Melting point	°C, 216.0 to 216.6 K,  °F
Boiling point
Solubility in water	0.007 mg dm−3 (at 20 °C)
log P	4.783
Vapor pressure	1.47 kPa (at 20.0 °C)
kH	29 nmol Pa−1 kg−1
Magnetic susceptibility (χ)	-96.63·10−6 cm3/mol
Refractive index (nD)	1.398
Viscosity	542 μPa s (at 20 °C)
Thermochemistry
Std enthalpy of formation ΔfHo298	−252.1–−248.5 kJ mol−1
Std enthalpy of combustion ΔcHo298	−5.53–−5.33 MJ mol−1
Standard molar entropy So298	361.20 J K−1 mol−1
Specific heat capacity, C	255.68 J K−1 mol−1
Hazards
NFPA 704	3 1 0
Explosive limits	0.96–6.5%
U.S. Permissible exposure limit (PEL)	TWA 500 ppm (2350 mg/m3)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)