3.1: Structure of Alkanes
The formation of carbon-carbon bonds leading to the creation of the carbon chain is the basis of organic chemistry. August Kekulé and Archibald Scott Couper independently developed this idea of carbon chain formation.
Hydrocarbons are the simplest organic compounds composed of carbons and hydrogens. Based on the bond order between carbons, the hydrocarbons are further classified into alkanes, alkenes, and alkynes.
Alkanes are the simplest hydrocarbons with sp3 hybrid carbon atoms. These sp3 carbon atoms can form sigma bonds with sp3 orbitals of other carbon atoms or with the 1s atomic orbitals of hydrogen atoms. Since alkanes possess only single bonds between carbon atoms, they are also known as saturated hydrocarbons. The general formula of alkanes is CnH2n+2, indicating that for every "n" carbon atom, alkanes have "2n+2" hydrogen atoms.
The Lewis structure of alkanes can be simplified using the condensed structural formula. In this representation, bonds between carbon-hydrogen and carbon-carbon are omitted to simplify the structure. Further simplification is done with the help of the line-angle formula. The lines represent carbon-carbon bonds. The line end and vertex represent the carbon atoms. The hydrogens are not explicitly shown and are assumed to be present, satisfying the carbon valency.