# How many isomers can a formula of C_5H_12 support?

For $\text{pentane}$, ${C}_{5} {H}_{12}$, I count 3 isomers.......
There are $\text{n-pentane}$, $\text{isopentane}$, and $\text{neopentane}$, i.e. $\text{pentane}$, $\text{2-methylbutane}$, and $\text{2,2-dimethylpropane.}$