Conformational isomers are that kinds of isomer involves in orientation of the molecules in three dimensional space. Different arranged atom if can convert into one another by the rotation of the single bond is called conformation. The different arrangement of the atom is didifferent in different conformation, but they can convert into each another only by rotation of single bond. The two common conformational isomer is Eclipsed and Stagered conformation. Just for example, in ethane the different hydrogen in different carbon arrange differently in space. The arrangement of the hydrogen atom can convert by the rotation of carbon carbon single bond. Carbon carbon single bond is called sigma bond. Eclipsed conformation there found that hydrogen atom of each carbon or the carbon- hydrogen bond of each parts are about to coincided if the are put closer to each other. But in Staggered conformation carbon hydrogen bond in different parts of the molecule cannot be coincided.
Potential energy vs rotation in conformational isomers
The potential energy and rotation of the carbon carbon bond if ploted there will found peaks and valley of energy. The eclipsed conformation lies in the top of the peaks and the staggered conformations are in the valley of the hills.