In ethane C2H6 , there are two carbon atoms bonded to each other, and each carbon atom is bonded to three hydrogen atoms. The central carbon atom forms four sigma bonds single bonds in total: one with the other carbon atom and three with hydrogen atoms. To accommodate these four sigma bonds, the central carbon atom undergoes sp3 hybridization, which involves the mixing of one 2s orbital and three 2p orbitals to form four sp3 hybrid orbitals. These hybrid orbitals are then used to form the sigma bonds with the other carbon and hydrogen atoms.