Butane is a four-carbon alkane with the molecular formula C₄H₁₀. It has a linear carbon chain with four carbon atoms and ten hydrogen atoms. Each carbon atom in the chain is bonded to four other atoms, with three of the bonds being to hydrogen atoms and one bond being to another carbon atom. The carbon-carbon bonds in butane are all sigma bonds, which are formed by the overlap of two atomic orbitals along the internuclear axis.