Editing Metal (section)

{{short description|Type of material}}
{{About|metallic materials|the musical genre|Heavy metal music|other uses}}
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[[File:Iron electrolytic and 1cm3 cube.jpg|thumb|right|alt=refer to caption|[[Iron]], shown here as fragments and a 1&nbsp;cm<sup>3</sup> cube, is an example of a [[chemical element]] that is a metal.]]
[[File:Sauce boat.jpg|thumb|right|alt=A metal gravy boat|Metal in the form of a [[gravy boat]] made from stainless steel, an [[alloy]] largely composed of iron, chromium and nickel]]
{{sidebar periodic table|metalicity}}

A '''metal''' ({{etymology|grc|''{{Wikt-lang|grc|μέταλλον}}'' ({{grc-transl|μέταλλον}})|mine, quarry, metal}}) is a [[material]] that, when polished or fractured, shows a lustrous appearance, and conducts [[electrical resistivity and conductivity|electricity]] and [[thermal conductivity|heat]] relatively well. These properties are all associated with having electrons available at the [[Fermi level]], as against nonmetallic materials which do not.<ref name="Kittel-2018">{{Cite book |last=Kittel |first=Charles |title=Introduction to solid state physics |date=2018 |publisher=Wiley |others=Paul McEuen |isbn=978-1-119-45416-8 |edition=Global edition, [9th edition] |location=Hoboken, NJ}}</ref>{{Rp|location=Chpt 8 & 19}}<ref name="Ashcroft-1976">{{Cite book |last1=Ashcroft |first1=Neil W. |title=Solid state physics |last2=Mermin |first2=N. David |date=1976 |publisher=Holt, Rinehart and Winston |isbn=978-0-03-083993-1 |location=New York}}</ref>{{Rp|pages=Chpt 7 & 8}} Metals are typically [[ductile]] (can be drawn into a wire) and [[malleable]] (can be shaped via hammering or pressing).<ref name="Callister-1997">{{Cite book |last=Callister |first=William D. |title=Materials science and engineering: an introduction |date=1997 |publisher=John Wiley & Sons |isbn=978-0-471-13459-6 |edition=4th |location=New York}}</ref>

A metal may be a [[chemical element]] such as [[iron]]; an [[alloy]] such as [[stainless steel]]; or a molecular compound such as [[polythiazyl|polymeric sulfur nitride]].<ref>{{cite journal |last1=Chiang |first1=CK| date=1977 |title=Transport and optical properties of polythiazyl bromides: (SNBr<sub>0.4</sub>)x |journal=Solid State Communications |volume= 23|issue=9 |pages= 607–612 |doi=10.1016/0038-1098(77)90530-0|bibcode=1977SSCom..23..607C }}; {{cite book |last1=Greenwood |first1=NN |last2=Earnshaw |first2=A | date=1998 |title=Chemistry of the Elements |location=Oxford |publisher=Butterworth-Heinemann |page=727 |isbn=978-0-7506-3365-9}}; {{cite book |last1=Mutlu |first1=H |last2=Theato |first2=P |editor-last1=Zhang| editor-first1= X|editor-last2=Theato|editor-first2=P|title=Sulfur-Containing Polymers: From Synthesis to Functional Materials |location=Weinheim |publisher=Wiley-VCH |pages=191–234 (191)|date=2021|isbn=978-3-527-34670-7|chapter=Polymers with sulfur-nitrogen bonds}}</ref> The general science of metals is called [[metallurgy]], a subtopic of [[materials science]]; aspects of the electronic and thermal properties are also within the scope of [[condensed matter physics]] and [[solid-state chemistry]], it is a [[multidisciplinary]] topic. In colloquial use materials such as steel alloys are referred to as metals, while others such as polymers, wood or ceramics are [[nonmetallic material]]s.

A metal conducts electricity at a temperature of [[absolute zero]],<ref>{{cite book |title=Physics of Metal-Nonmetal Transitions |last=Yonezawa |first=F. |year=2017 |publisher=IOS Press |location=Amsterdam |isbn=978-1-61499-786-3 |page=257 |quote=Sir [[Nevill Mott]] (1905–1996) wrote a letter to a fellow physicist, [[Peter Edwards (chemist)|Prof. Peter P. Edwards]], in which he notes... I've thought a lot about 'What is a metal?' and I think one can only answer the question at ''T'' = 0 (the absolute zero of temperature). There a metal conducts and a nonmetal doesn't.}}</ref> which is a consequence of [[Delocalized electron|delocalized]] states at the Fermi energy.<ref name="Kittel-2018" /><ref name="Ashcroft-1976" /> Many elements and compounds become metallic under high pressures, for example, [[iodine]] gradually becomes a metal at a pressure of between 40 and 170 thousand times [[atmospheric pressure]]. [[Sodium]] becomes a nonmetal at pressure of just under two million times atmospheric pressure, and at even higher pressures it is expected to become a metal again.

When discussing the [[periodic table]] and some chemical properties, the term metal is often used to denote those elements which in pure form and at standard conditions are metals in the sense of electrical conduction mentioned above. The related term metallic may also be used for types of [[dopant]] atoms or alloying elements.

In [[astronomy]] metal refers to all chemical elements in a star that are heavier than [[helium]]. In this sense the first four "metals" collecting in stellar cores through nucleosynthesis are [[carbon]], [[nitrogen]], [[oxygen]], and [[neon]]. A star [[nuclear fusion|fuses]] lighter atoms, mostly hydrogen and helium, into heavier atoms over its lifetime. The [[metallicity]] of an astronomical object is the proportion of its matter made up of the heavier chemical elements.<ref name="Martin">{{cite web |author=Martin |first=John C. |title=What we learn from a star's metal content |url=https://sites.google.com/a/uis.edu/john-c-martin-s-homepage/research/rr-lyrae-kinematics/what-we-learn-from-a-star-s-metal-content |access-date=March 25, 2021 |work=John C. Martin's Homepage}}</ref><ref>{{cite journal |last1=Martin |first1=John C. |last2=Morrison |first2=Heather L. |date=May 18, 1998 |orig-year=1998 |title=A New Analysis of RR Lyrae Kinematics in the Solar Neighborhood |url=https://iopscience.iop.org/article/10.1086/300568/fulltext/tal-content |journal=[[The Astronomical Journal]] |language=en |publication-date=October 1, 1998 |volume=116 |issue=4 |pages=1724–1735 |doi=10.1086/300568 |arxiv=astro-ph/9806258 |bibcode=1998AJ....116.1724M |s2cid=18530430 |via=IOPscience}}</ref>

The strength and resilience of some metals has led to their frequent use in, for example, high-rise building and bridge [[construction]], as well as most vehicles, many [[home appliance]]s, tools, pipes, and railroad tracks. [[Precious metal]]s were historically used as [[coin]]age, but in the modern era, [[coinage metals]] have extended to at least 23 of the chemical elements.<ref>{{cite journal |last1=Roe |first1=J. |last2=Roe |first2=M. |date=1992 |title=World's coinage uses 24 chemical elements |journal=World Coinage News |volume=19 |issue=4, 5 |pages=24–25, 18–19}}</ref> There is also extensive use of multi-element metals such as [[titanium nitride]]<ref name="Stampfl-2001">{{Cite journal |last1=Stampfl |first1=C. |last2=Mannstadt |first2=W. |last3=Asahi |first3=R. |last4=Freeman |first4=A. J. |date=2001 |title=Electronic structure and physical properties of early transition metal mononitrides: Density-functional theory LDA, GGA, and screened-exchange LDA FLAPW calculations |url=https://link.aps.org/doi/10.1103/PhysRevB.63.155106 |journal=Physical Review B |volume=63 |issue=15 |pages=155106 |doi=10.1103/PhysRevB.63.155106|bibcode=2001PhRvB..63o5106S |url-access=subscription }}</ref> or [[degenerate semiconductor]]s in the semiconductor industry.

The history of refined metals is thought to begin with the use of copper about 11,000 years ago. Gold, silver, iron (as meteoric iron), lead, and brass were likewise in use before the first known appearance of bronze in the fifth millennium BCE. Subsequent developments include the production of early forms of steel; the discovery of [[sodium]]—the first [[light metal]]—in 1809; the rise of modern [[alloy steel]]s; and, since the end of World War II, the development of more sophisticated alloys.