Question

What are examples of geometric isomers?

Answer 1

Well, cis-trans 2-butylene for a start....

Explanation:

By specification, geometric isomers are characterized by equivalent connectivity...but different geometry. And `"2-butylene"` is a go to example.... We gots…

`H_3stackrel(1)C-stackrel(2)CH=stackrel(3)CH-stackrel(4)CH_3`

Now while the connectivities of these isomers are manifestly the same, and you can see this in the numbering scheme, their chemistry, and physical properties are distinct. The cis isomer has a normal boiling point of `3.7` `""^@C`, and the trans isomer has a normal boiling point of `0.9` `""^@C`. (This order of volatility is unusual given that the trans isomer is usually more involatile.

And disubstituted ring systems, i.e. `"dimethylcyclohexane"`, offer a wealth of examples with regard to the cis or trans disposition of the hydrocarbyl groups with respect to the plane of the ring.

...and this is the `"1,4-cis isomer"`. How would you represent the `"1,4-trans isomer"`?