Isopentane

Isopentane

Skeletal formula of isopentane
Skeletal formula of isopentane with all implicit carbons shown, and all explicit hydrogens added
Ball and stick model of isopentane
Names
Preferred IUPAC name 2-Methylbutane
Other names Isopentane
Identifiers
CAS Number	78-78-4 Y
3D model (JSmol)	Interactive image
Beilstein Reference	1730723
ChEBI	CHEBI:30362 Y
ChemSpider	6308 Y
ECHA InfoCard	100.001.039
EC Number	201-142-8
Gmelin Reference	49318
MeSH	isopentane
PubChem CID	6556
RTECS number	EK4430000
UNII	ZH67814I0O Y
UN number	1265
CompTox Dashboard (EPA)	DTXSID901335409, DTXSID201032357 DTXSID8025468, DTXSID901335409, DTXSID201032357
InChI InChI=1S/C5H12/c1-4-5(2)3/h5H,4H2,1-3H3 Y Key: QWTDNUCVQCZILF-UHFFFAOYSA-N Y
SMILES CCC(C)C
Properties
Chemical formula	C5H12
Molar mass	72.151 g·mol−1
Appearance	Colorless liquid
Odor	Gasoline-like
Density	616 mg mL−1
Melting point	−161 to −159 °C; −258 to −254 °F; 112 to 114 K
Boiling point	27.8 to 28.2 °C; 81.9 to 82.7 °F; 300.9 to 301.3 K
Vapor pressure	76.992 kPa (at 20 °C)
Henry's law constant (kH)	7.2 nmol Pa−1 kg−1
UV-vis (λmax)	192 nm
Refractive index (nD)	1.354
Viscosity	0.214 cP (at 20 °C)
Thermochemistry
Heat capacity (C)	164.85 J K−1 mol−1
Std molar entropy (S⦵298)	260.41 J K−1 mol−1
Std enthalpy of formation (ΔfH⦵298)	−179.1–−177.3 kJ mol−1
Std enthalpy of combustion (ΔcH⦵298)	~ 3.3 MJ mol−1, 19,664 Btu/lb
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H224, H301, H302, H305, H336, H411
Precautionary statements	P210, P261, P273, P301+P310, P331
NFPA 704 (fire diamond)	1 4 0
Flash point	−51 °C (−60 °F; 222 K)
Autoignition temperature	420 °C (788 °F; 693 K)
Explosive limits	1.4–8.3%
Related compounds
Related alkanes	Isobutane 2-Methylpentane 3-Methylpentane 3-Ethylpentane
Related compounds	2-Ethyl-1-butanol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Isopentane, also called methylbutane or 2-methylbutane, is a branched-chain saturated hydrocarbon (an alkane) with five carbon atoms, with formula C
₅H
₁₂ or CH(CH
₃)
₂(C
₂H
₅).

Isopentane is a volatile and flammable liquid. It is one of three structural isomers with the molecular formula C₅H₁₂, the others being pentane (n-pentane) and neopentane (2,2-dimethylpropane).

Isopentane is commonly used in conjunction with liquid nitrogen to achieve a liquid bath temperature of −160 °C. Natural gas typically contains 1% or less isopentane, but it is a significant component of natural gasoline.