(This statement is from wikipedia, BTW).
What is so special about metallic bond that is limiting high-P low-T state of a matter (as long as individual atoms exist, not white dwarf of neutron star scenario)?
While simple Le-Chatelier principle predicts denser structure with higher pressure, does it always translate to near-ideal sphere-packing scenario? If not, why?
What are the basics required to understand explanation of these phenomena?