The following structural isomers are possible for C5C8with one triple bond:
(I)[\ce{H^1C ^3CH2 - ^4CH2 - ^5CH}]
(II) [\ce{H3^1C - ^2C ^3C - ^4CH2 - ^5CH3}]
(III)[\begin{array}{cc}
\ce{H3^4C - ^3CH - ^2C ^1CH}\
|\phantom{......}\
\ce{CH3}\phantom{....}\end{array}]
The IUPAC name of
Compound (I) is Pent-1-yne,
Compound (II) is Pent-2-yne, and
Compound (III) is 3-Methylbut-1-yne.