What causes geometric isomers?

1 Answer
Apr 14, 2017

The potential of certain molecules to give a number of distinct geometries..........

Explanation:

Geometric isomers are molecules with the same chemical formula, and the SAME CONNECTIVITY that have different geometries.

The best and most simple example of geometric isomerism occurs for #"2-butylene"#, #"H"_3"CCH=CHCH"_3#.

Because the methyl groups can be on the SAME or DIFFERENT sides of the olefinic bond, the structure can generate 2 geometric isomers:

chemistry.stackexchange.com

For both isomers, the #C-C# connectivity is the same: #C1# connects to #C2# connects to #C3# connects to #C4#. And yet these isomers are manifestly different geometrically. Their physical constants are also particular. The cis isomer has a normal boiling point of #3.7# #""^@C#, that of the trans isomer is #0.9# #""^@C#,