eclipsed conformation

In chemistry, eclipsed conformation refers to a specific spatial arrangement of atoms in a molecule where groups attached to adjacent atoms are aligned directly in front of each other when viewed down the bond connecting those atoms. This arrangement is typically a high-energy state due to repulsive forces between electrons in the bonds.

For example, in ethane (CH₃CH₃), the eclipsed conformation occurs when the hydrogen atoms on one carbon are directly in front of the hydrogen atoms on the other carbon. This is in contrast to the staggered conformation, where the atoms are as far apart as possible and represent a lower energy state. The energy difference between these conformations arises from torsional strain caused by electron repulsion. While eclipsed conformations are energy maxima and not typically stable isomers, they are important transition states in molecular rotations.12