Question

What is a planar molecule?

Answer 1

A planar molecule is a way to describe a molecule that lays flat on a particular plane. A plane is the surface that two coordinate axes form (from algebra).

For instance, we conventionally say that `"H"_2"C"="CCl"_2` (1,1-dichloroethylene) lays on the `yz`-plane, and that its `2p_x` atomic orbitals form the `"C"-"C"` `pi` bond, since the principal (`C_2`) rotation axis is along the `"C"="C"` bond, defined as the `z` axis: