Editing Period 5 element (section)

===Molybdenum===
{{main| Molybdenum}}

'''Molybdenum''' is a [[Group 6 element|Group 6]] [[chemical element]] with the symbol '''Mo''' and [[atomic number]] 42. The name is from Neo-Latin ''Molybdaenum'', from [[Ancient Greek]] {{lang|grc|Μόλυβδος}} {{lang|grc-Latn|molybdos}}, meaning ''lead'', itself proposed as a [[loanword]] from [[Anatolian languages|Anatolian]] [[Luvian language|Luvian]] and [[Lydian language|Lydian]] languages,<ref name="melchert">{{cite web|author=Melchert, Craig |url=http://www.unc.edu/~melchert/molybdos.pdf |title=Greek mólybdos as a Loanword from Lydian |publisher=[[University of North Carolina]] at [[Chapel Hill, North Carolina|Chapel Hill]] |access-date=2011-04-23 |url-status=dead |archive-url=https://web.archive.org/web/20081012125202/http://www.unc.edu/~melchert/molybdos.pdf |archive-date=2008-10-12 }}</ref> since its ores were confused with lead ores.<ref name="CRCdescription">{{Cite book|contribution = Molybdenum|year = 1994|title = CRC Handbook of Chemistry and Physics|editor-last = Lide|editor-first = David R.|volume = 4|page = 18|publisher = Chemical Rubber Publishing Company|isbn=0-8493-0474-1|author = editor-in-chief David R. Lide.}}</ref> The free element, which is a silvery [[metal]], has the [[List of elements by melting point|sixth-highest]] [[melting point]] of any element. It readily forms hard, stable [[carbide]]s, and for this reason it is often used in high-strength [[steel]] alloys. Molybdenum does not occur as a [[Native metal|free metal]] on Earth, but rather in various [[oxidation state]]s in minerals. Industrially, molybdenum [[Chemical compound|compounds]] are used in [[high-pressure]] and high-temperature applications, as [[pigments]] and [[Catalysis|catalysts]].

Molybdenum minerals have long been known, but the element was "discovered" (in the sense of differentiating it as a new entity from the mineral salts of other metals) in 1778 by [[Carl Wilhelm Scheele]]. The metal was first isolated in 1781 by [[Peter Jacob Hjelm]].

Most molybdenum compounds have low [[solubility]] in water, but the molybdate ion MoO<sub>4</sub><sup>2−</sup> is soluble and forms when molybdenum-containing minerals are in contact with [[oxygen]] and water.