The case for steric repulsion causing the staggered conformation of ethane.

It has recently been argued that the barrier to rotation around the C C bond in ethane is not to be explained by the generally accepted picture of steric hindrance between vicinal C H bonds in the eclipsed conformation but is caused by more favorable orbital interaction in the staggered conformation. In that conformation the C H bonds at opposite ends of the molecule have an in-plane trans conformation which is favorable for interaction of the s* antibonding orbital of one C H unit with the occupied sC H bonding orbital at the other side (six such pairs). This view has been advocated with