Octanes are eight-carbon alkanes with the formula C₈H₁₈. We offer two forms here. n-Octane is the straight-chain isomer, used for organic synthesis and as a solvent. Isooctane (2,2,4-Trimethylpentane) is the branched isomer, used to blend gasoline and set the octane rating scale. Both come in 99% purity, packed in steel drums or ISO tanks.