Isomers are compounds having the same chemical formula but having different arrangements of atoms. There are many types of isomers that are defined based on the way in which the atomic arrangements differ.

Structural isomerism is a form of isomerism in which the atoms are arranged in a different order. For example, the ions SNC^- and SCN^- have the same atoms but they are connected to one another in a different order. Stereoisomers have the same bonds but in different spatial arrangements. For example, the molecule CHClBrI, in which the carbon (C) atom is the central atom with the other four atoms attached in a tetrahedral arrangement around the carbon, can be prepared in two distinct ways such that the two molecules are non-superimposable.

One of the subcategories within structural isomerism is chain isomerism which is due to different arrangements of atoms...