Question

What is the dihedral angle in this molecule?

• A. ${120}^o$
• B. ${60}^o$
• C. ${180}^o$
• D. No dihedral angle exists.

Answer 1

The correct option is C ${180}^o$

Dihedral angle or torsional angle is the angle between planes through two sets of three atoms, having two atoms in common.

Although the technically correct way would be to look at the planes, for our ease we can just look at the bonds directly in most cases.

So, in this case, the configuration is Cl-C-Cl. Angle will be ${180}^o$. This is called the anti-conformation.