$\therefore$ Mol. formula $= C_5H_{12}$, Structure $\begin{array}{*{20}{c}} {\,\,\,\,\,\,C{H_3}} \\ | \\ {C{H_3} - C - C{H_3}} \\ | \\ {\,\,\,\,\,\,\,C{H_3}} \end{array}$ neo-pentane