I'm confused by the structure of Pb3O4. There are some sites claiming that it is a six membered ring of alternating Lead and Oxygen atoms with another Oxygen atom in the center bonding with 2 out of the 3 Lead atoms.
There are other sources which claim that it is actually two 4 membered rings of alternating lead and oxygen atoms with a lead atom in common between the 2 rings.
Moreover, isn't Lead a metal? Then How can it combine with oxygen in such "bonds" whereas ionic bonds are non-directional?