Editing Antimony (section)

===Properties===
[[File:Antimon.PNG|thumb|left|alt=A clear vial containing small chunks of a slightly lustrous black solid, labeled "Sb".|A vial containing the metallic [[allotrope]] of antimony]]
[[File:Antimony massive.jpg|left|thumb|alt=An irregular piece of silvery stone with spots of variation in luster and shade.|Native antimony with [[redox|oxidation]] products]]
[[File:SbAs lattice.png|thumb|left|Crystal structure common to Sb, [[stibarsen|AsSb]] and gray As]]

Antimony is a member of [[Group (periodic table)|group 15]] of the [[periodic table]], one of the elements called [[pnictogen]]s, and has an [[electronegativity]] of 2.05. In accordance with periodic trends, it is more electronegative than [[tin]] or [[bismuth]], and less electronegative than [[tellurium]] or [[arsenic]]. Antimony is stable in air at room temperature but, if heated, it reacts with [[oxygen]] to produce [[antimony trioxide]],{{chem2|Sb2O3}}.<ref name=w758>[[#Wiberg|Wiberg and Holleman]], p. 758</ref>

Antimony is a silvery, lustrous gray metalloid with a [[Mohs scale]] hardness of 3, which is too soft to mark hard objects. Coins of antimony were issued in China's [[Guizhou]] in 1931; durability was poor, and minting was soon discontinued because of its softness and toxicity.<ref>{{cite web|url=http://www.ukcoinpics.co.uk/metal.html|title=Metals Used in Coins and Medals|publisher=ukcoinpics.co.uk|access-date=16 October 2009|archive-url=https://web.archive.org/web/20101226044427/http://www.ukcoinpics.co.uk/metal.html|archive-date=26 December 2010|url-status=dead}}</ref> Antimony is resistant to attack by acids.

The only stable [[allotropy|allotrope]] of antimony under standard conditions<ref>{{cite journal |last1=Ashcheulov |first1=A. A. |last2=Manyk |first2=O. N. |first3=T. O. |last3=Manyk |first4=S. F. |last4=Marenkin |first5=V. R. |last5=Bilynskiy-Slotylo |date=2013 |title=Some Aspects of the Chemical Bonding in Antimony |journal=Inorganic Materials |volume=49 |issue=8 |pages=766–769 |doi=10.1134/s0020168513070017 }}</ref> is metallic, [[brittle]], silver-white, and shiny. It crystallises in a [[trigonal]] cell, [[isomorphism (crystallography)|isomorphic]] with [[bismuth]] and the gray allotrope of [[arsenic]], and is formed when molten antimony is cooled slowly. Amorphous black antimony is formed upon rapid cooling of antimony vapor, and is only stable as a thin film (thickness in nanometres); thicker samples spontaneously transform into the metallic form.<ref>{{cite journal |last1=Shen |first1=Xueyang |last2=Zhou |first2=Yuxing |first3=Hanyi |last3=Zhang |first4=Volker L. |last4=Derlinger |first5=Riccardo |last5=Mazzarello |first6=Wei |last6=Zhang |date=2023 |title=Surface effects on the crystallization kinetics of amorphous antimony |url= |journal=Nanoscale |volume=15 |issue= 37|pages=15259–15267 |doi=10.1039/D3NR03536K |pmid=37674458 }}</ref> It oxidizes in air and may ignite spontaneously. At 100&nbsp;°C, it gradually transforms into the stable form. The supposed yellow allotrope of antimony, generated only by oxidation of [[stibine]] ({{chem2|SbH3}}) at −90&nbsp;°C, is also impure and not a true allotrope;<ref name=allotropes/><ref>{{cite journal |last1=Krebs |first1=H. |last2=Schultze-Gebhardt |first2=F. |last3=Thees |first3=R. |date=1955 |language=de |title=Über die Struktur und die Eigenschaften der Halbmetalle. IX: Die Allotropie des Antimons |url= |journal=Zeitschrift für anorganische und allgemeine Chemie |volume=282 |issue=1–6 |pages=177–195 |doi=10.1002/zaac.19552820121 |access-date=}}</ref> above this temperature and in ambient light, it transforms into the more stable black allotrope.<ref name="kirk" /><ref name="cww" /><ref>{{harvnb|Norman|1998}}, [{{GBUrl|vVhpurkfeN4C|PA50}} pp.&nbsp;50–51]</ref> A rare [[explosive form of antimony]] can be formed from the electrolysis of [[antimony trichloride]], but it always contains appreciable chlorine and is not really an antimony allotrope.<ref name=allotropes>{{RubberBible82nd|page=4-4}}</ref> When scratched with a sharp implement, an [[exothermic]] reaction occurs and white fumes are given off as metallic antimony forms; when rubbed with a [[Mortar and pestle|pestle in a mortar]], a strong detonation occurs.

Elemental antimony adopts a layered structure ([[space group]] R{{overline|3}}m No. 166) whose layers consist of fused, ruffled, six-membered rings. The nearest and next-nearest neighbors form an irregular octahedral complex, with the three atoms in each double layer slightly closer than the three atoms in the next. This relatively close packing leads to a high density of 6.697&nbsp;g/cm<sup>3</sup>, but the weak bonding between the layers leads to the low hardness and brittleness of antimony.<ref name=w758/>