CID 8058

C₆H₁₄

Hexane

C 6
H 14

Ball-and-stick Stick Space-filling

Drag to rotate; pinch or Ctrl + scroll to zoom. Arrow keys rotate, + − zoom, R resets.

20 atoms, 19 single bonds.

IUPAC name: hexane
Molar mass: 86.178(15) g/mol
Atoms: 20
Polarity: nonpolar
SMILES: CCCCCC
InChIKey: VLKZOEOYAKHREP-UHFFFAOYSA-N
PubChem CID: 8058

Made of

C H

Structural formula of hexane. Each unlabelled corner is a carbon atom, and the eight hydrogens on carbon are not drawn. It shows which atoms are joined to which, not the shape. The model above shows the shape.

A solvent and a nerve poison at once: ChEBI, the Chemical Entities of Biological Interest database, gives hexane both roles, non-polar solvent and neurotoxin. It also calls hexane an unbranched alkane, six carbon atoms in a single chain, the count its prefix hex- stands for. Those six carry fourteen hydrogen atoms, C₆H₁₄, for a molar mass of 86.18 g/mol. MeSH, the Medical Subject Headings vocabulary, places it in the series that begins with methane.

At room temperature it is a colourless and very volatile liquid, boiling at 68.73 °C on the figure from HSDB, the Hazardous Substances Data Bank. How that figure fits the rise from pentane to octane is compared on octane’s page, with the attractions between molecules behind it. NIOSH, the US National Institute for Occupational Safety and Health, likens its odour to gasoline. Its card for n-hexane gives the formula CH₃(CH₂)₄CH₃, the unbranched chain that the model draws.

Structure and bonding

The readout counts 20 atoms and 19 single bonds. Five C–C bonds join the six carbons into one chain, and each of the other fourteen ties on a hydrogen; Labels prints a C or an H on every atom. In Ball-and-stick the chain bends at each inner carbon, with C–C–C angles of 111.3 to 111.5° in PubChem’s computed model. Why a carbon chain bends is set out in the article on molecular shapes. Nothing in the drawing simplifies the bonding: all nineteen bonds are single in the real molecule too, and none carries a charge.

Turned edge-on, the model lays all six carbons almost in one plane, a flat zig-zag with its two end carbons 6.36 Å apart. Stick thins the atoms away and leaves one folded line, with two hydrogens fanning from each inner carbon and three from each end. Space-filling swells every atom to full size, and the chain becomes a long, ridged rod clad almost entirely in hydrogen. The model holds the chain in the single arrangement PubChem computed, and it shows n-hexane alone.

Where it turns up

Plants make hexane, and so do forest fires and volcanoes, according to ATSDR, the US Agency for Toxic Substances and Disease Registry. Industry takes it from crude oil: HSDB describes n-hexane isolated from light gasoline, or from the streams left once benzene, toluene and xylene are extracted. The separating is done by superfractionation, a very fine distillation, or by molecular sieves, porous solids that sort molecules.

Haz-Map, an occupational health database, puts n-hexane at about 3 per cent of modern US gasoline blends. Because it is in gasoline, nearly everyone breathes very small amounts, below the levels ATSDR links to harm. Hobby glues that dry quickly and rubber cement contain it, and printing, textile, furniture and shoe factories clean with it.

Outdoors it evaporates readily, and the air breaks it down within a few days. Spilled on water, it floats, being less dense than water, and evaporates. It does not build up in plants, fish or animals.

Why it matters

The US Environmental Protection Agency (EPA) gives its main use as extracting edible oils out of seed and vegetable crops, soybeans, peanuts and corn among them. JECFA, an international expert committee on food additives, classes it as an extraction solvent. Processed oils are one route by which people meet it, ATSDR notes.

HSDB lists it as a filling for thermometers, low-temperature ones included, in place of mercury and usually dyed blue or red. It is also a reaction medium in making pharmaceuticals, and a liquid for determining the refractive index of minerals, how strongly they bend light.

HSDB records 93 cases of n-hexane polyneuropathy, damage to many peripheral nerves, among sandal workers in a large outbreak in 1968; most recovered completely. In 2010 exposure harmed 137 workers at a plant in Suzhou, China, run by Wintek, one of Apple’s iPhone suppliers; Apple then required Wintek to stop using the solvent. In 2026 the European Chemicals Agency listed it as a Substance of Very High Concern, for organ damage after repeated exposure.

Properties

Properties of hexane Molar mass summed from IUPAC/CIAAW 2024 standard atomic weights; formula, atom and bond counts and PubChem's molecular weight from PubChem CID 8058.
Property	Value	Unit	Source
Molecular formula (Hill order)	C₆H₁₄
Molar mass	86.178(15) g/mol	g/mol	IUPAC/CIAAW 2024
Carbon atoms	6
Hydrogen atoms	14
Bonds	19
PubChem molecular weight	86.18 g/mol	g/mol	PubChem

Safety

Both the liquid and its vapour are highly flammable, and the vapour, heavier than air, can travel along the ground and ignite at a distance. Under EU classification it carries the signal word Danger, and swallowed liquid can be fatal if it reaches the airways. It also irritates skin, may cause drowsiness or dizziness, is suspected of harming fertility and damages organs with prolonged or repeated exposure. The NIOSH Pocket Guide card for n-hexane lists the workplace exposure limits, and the PubChem Laboratory Chemical Safety Summary the full hazard record.

Questions

Can hexane affect fertility?

It can, and separately from its harm to nerves, on HSDB's account. Its toxic metabolite, 2,5-hexanedione, crosslinks tubulin, the protein that builds the tiny tubes called microtubules, inside Sertoli cells, the supporting cells of the testis that nurture developing sperm. ATSDR reports damage to sperm-forming cells in laboratory animals. California's Office of Environmental Health Hazard Assessment states that n-hexane can cause male reproductive toxicity.

Why does hexane damage nerves?

The liver oxidises hexane, and HSDB names the product, 2,5-hexanedione, as the toxic one. It lowers the phosphorylation, the attaching of phosphate groups, of neurofilaments, part of the protein skeleton inside nerve fibres, and the proteins pile up, crosslink and cause giant swellings in those fibres. It also reacts with lysine in proteins to form pyrroles, which tie proteins together. The first signs are tingling or numbness in the hands and feet.

Is the hexane sold as a solvent pure n-hexane?

Not in its technical grade. HSDB describes that grade as roughly half n-hexane, the unbranched molecule of the model, and half isohexane and cyclohexane. Among the branched isomers that travel with it are 2,2-dimethylbutane, 2,3-dimethylbutane, 3-methylpentane and 2-methylpentane, each built from the same six carbons and fourteen hydrogens. Purer material is sold too, in grades running from 85 per cent up to spectro, research and nanograde.

Is hexane polar or nonpolar?

Nonpolar. ChEBI, the Chemical Entities of Biological Interest database, assigns it the role of a non-polar solvent. Water and hexane barely mix: CAMEO Chemicals, a hazard database, calls it insoluble, and on HSDB's measurement just 9.5 mg of it dissolves per litre of water at 25 °C. With alcohol, chloroform and ether it mixes in all proportions; HSDB records it as miscible with all three.

Made of the same elements

C₆H₁₂ Cyclohexane 18 atoms, 18 single bonds.
C₅H₁₂ Pentane 17 atoms, 16 single bonds.
C₄H₁₀ Butane 14 atoms, 13 single bonds.
C₄H₁₀ Isobutane 14 atoms, 13 single bonds.
C₈H₁₈ Isooctane 26 atoms, 25 single bonds.
C₁₀H₁₆ Limonene 26 atoms, 26 bonds.
C₈H₁₈ Octane 26 atoms, 25 single bonds.
C₇H₈ Toluene 15 atoms, 15 bonds.

All 18 compounds made of carbon and hydrogen

C₆H₆ Benzene 12 atoms, 12 bonds.
C₈H₈ Styrene 16 atoms, 16 bonds.
C₃H₈ Propane 11 atoms, 10 single bonds.
C₄H₆ 1,3-Butadiene 10 atoms, 9 bonds.
C₁₀H₈ Naphthalene 18 atoms, 19 bonds.
C₃H₆ Propylene 9 atoms, 8 bonds.
C₂H₆ Ethane 8 atoms, 7 single bonds.
C₂H₄ Ethylene 6 atoms, 5 bonds.
CH₄ Methane 5 atoms, 4 single bonds, tetrahedral.
C₂H₂ Acetylene 4 atoms, 3 bonds.