I'm trying to find the resonance structure of HClO4 that contributes most to its true structure.
All four O atoms are bonded to the central chlorine atom and the H atom is bonded to an oxygen atom.
Cl will have a formal charge of zero and an expanded octet.
I can't figure out a way to draw this out. With an expanded octet, I keep giving Cl a formal charge of either +1 or +2.