Resonance Structures?

Question

What is the line or Lewis structure for the perchlorate ion? I have seen it w/ three double oxygen bonds and one single oxygen bond around the chlorine, four single oxygen bonds, and one that actually DETACHES the oxygen ion and separates it as an octet. Just google the perchlorate ion, and u will get the result in I think the 2nd or 3rd page. What are these all, resonance structures? They seem really weird to me.

Answer 1

They're all true. They come out of the fact that Lewis structures are not an accurate enough way to explain bonding in something like perchlorate. Lewis structures are really good for bonding in first row elements (C, N, O, etc.) but start being less accurate further on down because you end up violating the octet rule, and sometimes in ways that don't make sense. The real description of bonding is based on molecular orbital theory, and the strange combinations of "resonance" structures that you see is a way to use Lewis structures to explain a more complicated reality.

If you're more interested in this take an inorganic chemistry course, where you'll delve into d orbitals, molecular orbital theory, and understand bonding across the whole periodic table, not just the top row where organic chemistry is largely limited to.