Editing Indium (section)

===Physical===
[[File:Indium wetting glass.jpg|thumb|left|Indium wetting the glass surface of a test tube]]
Indium is a shiny silvery-white, highly [[ductile]] [[post-transition metal]] with a bright [[Lustre (mineralogy)|luster]].<ref name="InProcess">{{cite journal|last=Alfantazi|first=A. M.|date=2003|title=Processing of indium: a review|journal=Minerals Engineering|volume=16|issue=8|pages=687–694|doi=10.1016/S0892-6875(03)00168-7|author2=Moskalyk, R. R.|bibcode=2003MiEng..16..687A }}</ref> It is so soft ([[Mohs hardness]] 1.2) that it can be cut with a knife and leaves a visible line like a pencil when rubbed on paper.<ref name="Binder">{{cite book |last=Binder |first=Harry H. |date=1999 |title=Lexicon der chemischen Elemente |publisher=S. Hirzel Verlag |isbn=978-3-7776-0736-8 |language=de }}</ref> It is a member of [[boron group|group 13]] on the [[periodic table]] and its properties are mostly intermediate between its vertical neighbors [[gallium]] and [[thallium]]. As with [[tin]], a high-pitched [[tin cry|cry]] is heard when indium is bent – a crackling sound due to [[crystal twinning]].<ref name="InProcess" /> Like gallium, indium is able to [[wetting|wet]] glass. Like both, indium has a low [[melting point]], 156.60&nbsp;°C (313.88&nbsp;°F); higher than its lighter homologue, gallium, but lower than its heavier homologue, thallium, and lower than tin.<ref name="Lange">{{cite book |last=Dean |first=John A. |title=Lange's handbook of chemistry |publisher=McGraw-Hill, Inc.|date=523|isbn=978-0-07-016190-0|edition=Fifteenth }}</ref> The boiling point is 2072&nbsp;°C (3762&nbsp;°F), higher than that of thallium, but lower than gallium, conversely to the general trend of melting points, but similarly to the trends down the other post-transition metal groups because of the weakness of the metallic bonding with few [[Delocalized electron|electrons delocalized]].<ref name="Greenwood222">Greenwood and Earnshaw, p. 222</ref>

The density of indium, 7.31&nbsp;g/cm<sup>3</sup>, is also greater than gallium, but lower than thallium. Below the [[critical temperature]], 3.41&nbsp;[[kelvin|K]], indium becomes a [[superconductor]]. Indium crystallizes in the body-centered [[tetragonal crystal system]] in the [[space group]] ''I''4/''mmm'' ([[lattice parameter]]s:&nbsp;''a''&nbsp;=&nbsp;325&nbsp;[[picometer|pm]], ''c''&nbsp;=&nbsp;495&nbsp;pm):<ref name="Lange" /> this is a slightly distorted [[face-centered cubic]] structure, where each indium atom has four neighbours at 324&nbsp;pm distance and eight neighbours slightly further (336&nbsp;pm).<ref name="Greenwood252">Greenwood and Earnshaw, p. 252</ref> Indium has greater solubility in liquid mercury than any other metal (more than 50 mass percent of indium at 0&nbsp;°C).<ref>{{Cite journal|title=Hg-In phase diagram|journal=Journal of Phase Equilibria and Diffusion|volume=33|issue=2|pages=159–160|doi=10.1007/s11669-012-9993-3|year=2012|last1=Okamoto|first1=H.|s2cid=93043767}}</ref> Indium displays a ductile [[Viscoplasticity|viscoplastic]] response, found to be size-independent in tension and compression. However it does have a [[Size effect on structural strength|size effect]] in bending and indentation, associated to a length-scale of order 50–100&nbsp;μm,<ref>{{Cite journal|last1=Iliev|first1=S. P.|last2=Chen|first2=X.|last3=Pathan|first3=M. V.|last4=Tagarielli|first4=V. L.|date=2017-01-23|title=Measurements of the mechanical response of Indium and of its size dependence in bending and indentation|journal=Materials Science and Engineering: A|volume=683|pages=244–251|doi=10.1016/j.msea.2016.12.017|hdl=10044/1/43082|hdl-access=free}}</ref> significantly large when compared with other metals.