Bonds The attractive forces that hold atoms together in compounds are called chemical bonds. There are two major classes of bonds–ionic bonds and covalent bonds. Most of the bonds involved in natural gas components are single covalent bonds. A single covalent bond consists of a pair of electrons shared by two atoms. A double bond is two pair of electrons shared between two atoms. Some minor components of natural gas may contain both single and double bonds. Aromatic molecules, such as benzene, contain covalent bonds where multiple electrons are shared among more than two atoms