Alkanes and cycloalkanes
Alkanes
Alkanes are organic molecules consisting solely of carbon and hydrogen atoms linked by single σ bonds. All the carbon atoms are tetrahedral and sp3 hybridized. Alkanes are stable molecules and unreactive to most chemical reagents. They have the general formula CnH2n2
Cycloalkanes
Cycloalkanes are cyclic alkane structures. They have the general formula CnH2n. Most cycloalkanes are unreactive to chemical reagents. However, three- and four-membered rings are reactive due to ring strain and behave like alkenes.
Alkanes
Alkanes are organic molecules with the general formula CnH2n2, which consist of carbon and hydrogen atoms linked together by C–C and C–H single bonds. They are often referred to as saturated hydrocarbons – saturated because all the bonds are single bonds, hydrocarbons because the only atoms present are carbon and hydrogen. All the carbon atoms in an alkane are sp3 hybridized and tetrahedral in shape. The C–C and C–H bonds are strong σ bonds, and so alkanes are unreactive to most chemical reagents.
Alkanes are sometimes referred to as straight chain or acyclic alkanes to distinguish them from cycloalkanes or alicyclic compounds.
Cycloalkanes
Cycloalkanes are cyclic alkanes (alicyclic compounds) having the general formula CnH2n where the carbon atoms have been linked together to form a ring. All sizes of ring are possible. However, the most commonly encountered cycloalkane in organic chemistry is the six-membered ring (cyclohexane). Most cycloalkanes are unreactive to chemical reagents. However, small three- and four-membered rings are reactive and behave like alkenes. Such cyclic structures are highly strained since it is impossible for the carbon atoms to adopt their preferred tetrahedral shape.