is a highly volatile paraffinic hydrocarbon containing six carbon atoms in the molecule; it may also contain six-carbon isoparaffins. Widely used as a solvent in adhesive and rubber solvent formulations and in the extraction of a variety of edible and commercial oils. Normal hexane (a straight-chain six-carbon molecule) can cause peripheral polyneuropathy, a progressive and potentially irreversible disorder of the nervous system; it therefore must be handled with appropriate precautions.

Hexane has five isomers:

• Hexane, CH₃CH₂CH₂CH₂CH₂CH₃, a straight chain of six carbon atoms.
• 2-Methylpentane (Isohexane), CH₃CH(CH₃)CH₂CH₂CH₃, a five-carbon chain with one methyl branch on the second.
• 3-Methylpentane, CH₃CH₂CH(CH₃)CH₂CH₃, a five-carbon chain with one methyl branch on the third.
• 2,3-Dimethylbutane, CH₃CH(CH₃)CH(CH₃)CH₃, a four-carbon chain with one methyl branch on the second and third.
• 2,2-Dimethylbutane, CH₃C(CH₃)₂CH₂CH₃, a four-carbon chain with two methyl branches on the second.