Which of the following is not an example of isomerism in coordination compounds
 

• Isomerism happens when two compounds have the same chemical formulae but have different structures. 

Positional isomers are constitutional isomers that differ from one another by the position of the functional groups on or in the carbon chain despite sharing identical carbon skeletons and functional groups. eg. Constitutional isomers of propyl bromide are (1) and isopropyl bromide (2).