Editing Metal (section)

==Periodic table distribution of elemental metals==
{{See also|Periodic table}}
The elements that form exclusively metallic structures under ordinary conditions are shown in yellow on the periodic table below. The remaining elements either form [[network covalent bonding|covalent network]] structures (light blue), molecular covalent structures (dark blue), or remain as single atoms (violet).<ref>{{Greenwood&Earnshaw2nd}}</ref> 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 these uninvestigated elements should be metals,<ref name=Siekierski>{{cite book|title=Concise Chemistry of the Elements|year=2002|publisher=Horwood|isbn=978-1-898563-71-6|last1=Siekierski|first1=S.|last2=Burgess|first2 =J. |pages=60–66}}</ref> except for oganesson (Og) which DFT calculations indicate would be a semiconductor.<ref name="semiconductor">{{cite journal |last1=Mewes |first1=Jan-Michael |last2=Smits |first2=Odile Rosette |first3=Paul |last3=Jerabek |first4=Peter |last4=Schwerdtfeger |date=25 July 2019 |title=Oganesson is a Semiconductor: On the Relativistic Band-Gap Narrowing in the Heaviest Noble-Gas Solids |journal=Angewandte Chemie |volume=58 |issue=40 |pages=14260–14264|doi=10.1002/anie.201908327|pmid=31343819|pmc=6790653}}</ref>
{{Periodic table (simple substance bonding)}}
The situation changes with pressure: at extremely high pressures, all elements (and indeed all substances) are expected to metallize.<ref name=Siekierski/> 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.