# How many isomers exist for #C_5H_10#?

##### 1 Answer

Feb 6, 2016

Not counting geometric isomers, I can count at least 9 isomers. There may be more.

#### Explanation:

A formula of

So I can make at least 4 olefins with this formula (one of which has a geometric isomer); given the formula, the double bond can be either at

Given a ring junction, there are 5 alicyclic structures possible: a five-membered ring; a four-membered ring; and 3 three-membered rings. One of the three-membered rings can have geometric isomers.