I always liked that word. First learned it in organic chemistry. The context is for moelcular orbitals and our mathematical description of them. Different "types" (determined by quantum numbers) have different shapes, energies, and orientations in space. And they also have what we think of as polarity/charge. Where orthogonal comes in is when you take two orbitals and have a situation where their overlap cancels out...the amount of +/+ interaction equals the amount of +/- interaction. This happens because of the shape and arrangement in space, and are said to be orthogonal.
So with that basic chem primer, are AI and ai orthogonal?
