section_path: Periodic table distribution
section_name: Periodic table distribution
paragraph_text: Periodic table distribution
  
  The elements that form exclusively metallic structures under ordinary conditions are shown in yellow on the periodic table below. The remaining elements either form covalent network structures (light blue), molecular covalent structures (dark blue), or remain as single atoms (violet). Astatine (At), francium (Fr), and the elements from fermium (Fm) onwards are shown in gray because they are extremely radioactive and have never been produced in bulk. Theoretical and experimental evidence suggests that almost all these uninvestigated elements should be metals, though there is some doubt for oganesson (Og).
  
  Metallic Network covalent Molecular covalent Single atoms Unknown Background color shows bonding of simple substances in the periodic table. If there are several, the most stable allotrope is considered.
  
  The situation changes with pressure: at extremely high pressures, all elements (and indeed all substances) are expected to metallize. Arsenic (As) has both a stable metallic allotrope and a metastable semiconducting allotrope at standard conditions. A similar situation affects carbon (C): graphite is metallic, but diamond is not.