Some examples are given in Table 2. Scientists determined that the chemical formula of benzene was C6H6 in the 19th century. The branch attached to position 3 of our chain contains two carbon atoms numbered in red —so we take our name for two carbons eth- and attach -yl at the end to signify we are describing a branch.
Since a 4-carbon chain of the alkane series is called butane, a ring of 4 carbon atoms is called cyclobutane. InHodgkin and her colleague published the three-dimension structure of Vitamin B12 solved by X-ray diffractions up left figure, H atoms are not shown.
As shown in part b in Figure The removal of a hydrogen atom from a hydrocarbon molecule leaves an alkyl group that readily attaches to a functional group, or forms a branch on a hydrocarbon chain.
The structure that minimizes electrostatic repulsion is the one in which the methyl groups, corresponding to carbon atoms 1 and 4, are as far apart as possible; that is, the staggered conformation. Hexane has 5 isomers: hexane, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, and 2,3-dimethylbutane.