Are CH3 and CH3- symmetrical or unsymmetrical molecules? Explain the reasoning

Question

Are CH3 and CH3- symmetrical or unsymmetrical molecules? Explain the reasoning

Answer 1

CH3 by itself is symmetrical -- it has threefold rotational symmetry plus the molecule is planar.  This puts CH3 in the point group D3h.

CH3 anion is symmetrical also -- but it is not planar, it is pyramidal.  This puts CH3 anion in the point group C3v.