Editing Niobium (section)

===Chemical===
The metal takes on a bluish tinge when exposed to air at room temperature for extended periods.<ref name="Rubber">{{cite book|title = CRC Handbook of Chemistry and Physics|first = David R.|last = Lide|publisher = CRC Press|date = 2004|isbn = 978-0-8493-0485-9|pages = '''4'''–21|edition = 85th|chapter = The Elements|chapter-url-access = registration|chapter-url = https://archive.org/details/crchandbookofche81lide|url = https://archive.org/details/crchandbookofche81lide|url-access = registration}}</ref> Despite a high melting point in elemental form (2,468&nbsp;°C), it is less dense than other [[refractory metals]]. Furthermore, it is corrosion-resistant, exhibits superconductivity properties, and forms [[dielectric]] [[oxide]] layers.

Niobium is slightly less [[electropositive]] and more compact than its predecessor in the periodic table, [[zirconium]], whereas it is virtually identical in size to the heavier tantalum atoms, as a result of the [[lanthanide contraction]].<ref name="Nowak" /> As a result, niobium's chemical properties are very similar to those for tantalum, which appears directly below niobium in the [[periodic table]].<ref name="Gupta">{{cite book|title = Extractive Metallurgy of Niobium|first = C. K.|last = Gupta|author2=Suri, A. K. |publisher = CRC Press|date = 1994 |isbn = 978-0-8493-6071-8|pages = 1–16}}</ref> Although its corrosion resistance is not as outstanding as that of tantalum, the lower price and greater availability make niobium attractive for less demanding applications, such as vat linings in chemical plants.<ref name="Nowak" />