Nonmetal: Difference between revisions

This diversity in form stems from variability in internal structures and bonding arrangements. Covalent nonmetals existing as discrete atoms like xenon, or as small molecules, such as oxygen, sulfur, and bromine, have low melting and boiling points; many are gases at room temperature, as they are held together by weak [[London dispersion force]]s acting between their atoms or molecules, although the molecules themselves have strong covalent bonds.<ref>[[#ZumDeC|Zumdahl & DeCoste 2010, pp. 455, 456, 469, A40]]; [[#Earl&W|Earl & Wilford 2021, p. 3-24]]</ref> In contrast, nonmetals that form extended structures, such as long chains of selenium atoms,<ref>{{Cite journal |lastlast1=Corb |firstfirst1=B.W. |last2=Wei |first2=W.D. |last3=Averbach |first3=B.L. |date=1982 |title=Atomic models of amorphous selenium |url=https://linkinghub.elsevier.com/retrieve/pii/0022309382900163 |journal=Journal of Non-Crystalline Solids |language=en |volume=53 |issue=1-21–2 |pages=29–42 |doi=10.1016/0022-3093(82)90016-3|bibcode=1982JNCS...53...29C }}</ref> sheets of carbon atoms in graphite,<ref>[[#Wiberg|Wiberg 2001, pp. 780]]</ref> or three-dimensional lattices of silicon atoms<ref>[[#Wiberg|Wiberg 2001, pp. 824, 785]]</ref> have higher melting and boiling points, and are all solids, as it takes more energy to overcome their stronger bonding.<ref>[[#Earl&W|Earl & Wilford 2021, p. 3-24]]</ref>{{Dubious|Dubious cites|date=August 2024|reason=An O-level (i.e. 16 year old) chemistry textbook is not a good source to quote. It is used several times, better sources should be used.}} Nonmetals closer to the left or bottom of the periodic table (and so closer to the metals) often have [[Delocalized electron|metallic interactions]] between their molecules, chains, or layers; this occurs in boron,<ref>[[#Siekierski|Siekierski & Burgess 2002, p. 86]]</ref> carbon,<ref>[[#Charlier|Charlier, Gonze & Michenaud 1994]]</ref> phosphorus,<ref>[[#Taniguchi|Taniguchi et al. 1984, p. 867]]: "...&nbsp;black phosphorus&nbsp;... [is] characterized by the wide valence bands with rather delocalized nature."; [[#Carmalt|Carmalt & Norman 1998, p. 7]]: "Phosphorus&nbsp;... should therefore be expected to have some metalloid properties."; [[#Du|Du et al. 2010]]: Interlayer interactions in black phosphorus, which are attributed to van der Waals-Keesom forces, are thought to contribute to the smaller band gap of the bulk material (calculated 0.19&nbsp;eV; observed 0.3&nbsp;eV) as opposed to the larger band gap of a single layer (calculated ~0.75&nbsp;eV).</ref> arsenic,<ref>[[#Wiberg|Wiberg 2001, pp. 742]]</ref> selenium,<ref>[[#Evans|Evans 1966, pp. 124–25]]</ref> antimony,<ref>[[#Wiberg|Wiberg 2001, pp. 758]]</ref> tellurium<ref>[[#Stuke|Stuke 1974, p. 178]]; [[#Donohue|Donohue 1982, pp. 386–87]]; [[#Cotton|Cotton et al. 1999, p. 501]]</ref> and iodine.<ref>[[#Steudel|Steudel 2020, p. 601]]: "...&nbsp;Considerable orbital overlap can be expected. Apparently, intermolecular multicenter bonds exist in crystalline iodine that extend throughout the layer and lead to the delocalization of electrons akin to that in metals. This explains certain physical properties of iodine: the dark color, the luster and a weak electric conductivity, which is 3400 times stronger within the layers then perpendicular to them. Crystalline iodine is thus a two-dimensional semiconductor."; [[#Segal|Segal 1989, p. 481]]: "Iodine exhibits some metallic properties&nbsp;..."</ref>

Many of the nonmetallic elements are hard and brittle,<ref name="ReferenceA"/> where [[dislocations]] cannot readily move so they tend to undergo [[brittle fracture]] rather than deforming.<ref>{{Cite book |lastlast1=Weertman |firstfirst1=Johannes |url=https://en.wikipedia.org/wiki/Special:BookSources/978-0-19-506900-6 |title=Elementary dislocation theory |last2=Weertman |first2=Julia R. |date=1992 |publisher=Oxford University Press |isbn=978-0-19-506900-6 |location=New York}}</ref> Some do deform such as [[allotropes of phosphorus#White phosphorus|white phosphorus]] (soft as wax, pliable and can be cut with a knife, at room temperature),<ref name="Holderness 1979, p. 255">[[#Faraday|Faraday 1853, p. 42]]; [[#Holderness|Holderness & Berry 1979, p. 255]]</ref> in [[allotropes of sulfur#Amorphous sulfur|plastic sulfur]],<ref name="ReferenceE">[[#Partington1944|Partington 1944, p. 405]]</ref> and in selenium which can be drawn into wires from its molten state.<ref name="ReferenceF">[[#Regnault|Regnault 1853, p. 208]]</ref> Graphite is a standard [[solid lubricant]] where dislocations move very easily in the basal planes.<ref>{{Cite journal |last1=Scharf |first1=T. W. |last2=Prasad |first2=S. V. |date=January 2013 |title=Solid lubricants: a review |url=http://link.springer.com/10.1007/s10853-012-7038-2 |journal=Journal of Materials Science |language=en |volume=48 |issue=2 |pages=511–531 |doi=10.1007/s10853-012-7038-2 |bibcode=2013JMatS..48..511S |issn=0022-2461}}</ref>

A relatively recent development involves certain compounds of heavier p-block elements, such as silicon, phosphorus, germanium, arsenic and antimony, exhibiting behaviors typically associated with [[coordination compound|transition metal complexes]]. This is linked to a small energy gap between their [[HOMO and LUMO|filled and empty]] [[molecular orbitals]], which are the regions in a molecule where electrons reside and where they can be available for chemical reactions. In such compounds, this allows for unusual reactivity with small molecules like hydrogen (H₂), [[ammonia]] (NH₃), and [[ethylene]] (C₂H₄), a characteristic previously observed primarily in transition metal compounds. These reactions may open new avenues in [[catalyst|catalytic]] applications.<ref>[[#Power|Power 2010]]; [[#Crow|Crow 2013]]{{Broken anchor|date=2024-05-31|bot=User:Cewbot/log/20201008/configuration|target_link=#Crow|reason= }}; [[#Weetman|Weetman & Inoue 2018]]</ref>

File:Circuit Breaker 115 kV.jpg|A high-voltage [[Sulfur hexafluoride circuit breaker|circuit-breaker]] employing [[sulfur hexafluoride]] (SF₆) as its inert (air replacement) interrupting medium<ref>[[#Bolin|Bolin 2017, p.&nbsp;2-1]]{{Broken anchor|date=2024-05-31|bot=User:Cewbot/log/20201008/configuration|target_link=#Bolin|reason= The anchor (Bolin) [[Special:Diff/1226404653|has been deleted]].}}</ref>|alt=a small electricity-conducting installation in a snow-covered landscape

Just as the ancients distinguished metals from other minerals, similar distinctions developed as the modern idea of chemical elements emerged in the late 1700s. French chemist [[Antoine Lavoisier]] published the first modern list of chemical elements in his revolutionary<ref>[[#Strathern2000|Strathern 2000, p. 239]]</ref> 1789 ''[[Traité élémentaire de chimie]]''. The 33 elements known to Lavoisier were categorized into four distinct groups, including gases, metallic substances, nonmetallic substances that form acids when oxidized,<ref>{{Cite book |lastlast1=Moore |firstfirst1=F. J. |url=https://archive.org/details/historyofchemist030951mbp/page/n125/mode/2up?q=lavoisier |title=A History Of Chemistry |last2=Hall |first2=William T. |publisher=McGraw-Hill |year=1918 |pages=99 |access-date=2024-08-01}} Lavoisier's Table is reproduced on page 99.</ref> and [[Earth (historical chemistry)|earths]] (heat-resistant oxides).<ref>[[#Criswell|Criswell 2007, p. 1140]]</ref> Lavoisier's work gained widespread recognition and was republished in twenty-three editions across six languages within its first seventeen years, significantly advancing the understanding of chemistry in Europe and America.<ref>[[#Salzberg|Salzberg 1991, p. 204]]</ref>

| {{mono|1956}} || [[temperature coefficient of resistivity|Temperature coefficient]]<br/>[[temperature coefficient of resistivity|of resistivity]]<ref>{{Cite journal |lastlast1=Butera |firstfirst1=Richard A. |last2=Waldeck |first2=David H. |date=September 1997 |title=The Dependence of Resistance on Temperature for Metals, Semiconductors, and Superconductors |url=https://pubs.acs.org/doi/abs/10.1021/ed074p1090 |journal=Journal of Chemical Education |language=en |volume=74 |issue=9 |pages=1090 |doi=10.1021/ed074p1090 |bibcode=1997JChEd..74.1090B |issn=0021-9584}}</ref> || C

:''METAL, in natural history and chemistry, the name of a class of simple bodies; of which it is observed, that they posses; a lustre; that they are opaque; that they arc fusible, or may be melted; that their specific gravity is greater than that of any other bodies yet discovered; that they are better conductors of electricity, than any other body; that they are malleable, or capable of be­ingbeing extended and flattened by the hammer; and that they are ductile or tenacious, that is, capable of being drawn out into threads or wires.''

There is not full agreement about the use of phenomenological properties. [[John Emsley|Emsley]]<ref>[[Nonmetal#Emsley1971|Emsley 1971, p. 1]]</ref> pointed out the complexity of this task, asserting that no single property alone can unequivocally assign elements to either the metal or nonmetal category. Some authors divide elements into metals, metalloids, and nonmetals, but Oderberg<ref>[[#Oderberg|Oderberg 2007, p. 97]]</ref> disagrees, arguing that by the principles of categorization, anything not classified as a metal should be considered a nonmetal.

Kneen and colleagues<ref name="Kneen218">[[Nonmetal#Kneen|Kneen, Rogers & Simpson 1972, pp. 218–219]]</ref> proposed that the classification of nonmetals can be achieved by establishing a single criterion for metallicity. They acknowledged that various plausible classifications exist and emphasized that while these classifications may differ to some extent, they would generally agree on the categorization of nonmetals. The describe electrical conductivity as the key property, arguing that this is the most common approach.{{clear}}

One of the most commonly recognized properties used is the [[temperature coefficient of resistivity]], the effect of heating on electrical resistance and conductivity. As temperature rises, the conductivity of metals decreases while that of nonmetals increases.<ref name="Herman">[[Nonmetal#Herman|Herman 1999, p. 702]]</ref> However, [[plutonium]], carbon, arsenic, and antimony appear to defy the norm. When plutonium (a metal) is heated within a temperature range of −175 to +125&nbsp;°C its conductivity increases.<ref>[[Nonmetal#Russell|Russell & Lee 2005, p. 466]]</ref> Similarly, despite its common classification as a nonmetallic element, carbon (as graphite) is a semimetal which when heated experiences a decrease in electrical conductivity.<ref>[[Nonmetal#Atkins2006|Atkins et al. 2006, pp. 320–21]]</ref> Arsenic and antimony, which are occasionally classified as nonmetallic elements are also semimetals, and show behavior similar to carbon.<ref>[[Nonmetal#Zhigal'skii|Zhigal'skii & Jones 2003, p. 66]]</ref>{{Dubious|date=August 2024|reason=No such statements appear in the more recent 9th and other editions, so unverifiable.}}