Editing Chromate and dichromate (section)

==Applications==
[[File:Laidlaw school bus.jpg|thumb| right| [[School bus]] painted in [[Chrome yellow]]<ref name="Yellow">{{cite book | title = Toxic Substances Controls Guide: Federal Regulation of Chemicals in the Environment | first = Mary Devine | last = Worobec |author2=Hogue, Cheryl| page = 13 | publisher=BNA Books | year = 1992 | isbn = 978-0-87179-752-0 | url =https://books.google.com/books?id=CjWQ6_7AnI4C&pg=PA13}}</ref>]]
Approximately {{convert|136000|tonne}} of [[hexavalent chromium]], mainly sodium dichromate, were produced in 1985.<ref name = Ullmann>{{cite book |last1=Anger |first1=Gerd |last2=Halstenberg |first2=Jost |last3=Hochgeschwender |first3=Klaus |author4=Scherhag, Christoph |author5=Korallus, Ulrich |author6=Knopf, Herbert |author7=Schmidt, Peter |author8=Ohlinger, Manfred |title=Ullmann's Encyclopedia of Industrial Chemistry |year=2005 |publisher=Wiley-VCH |location=Weinheim |doi=10.1002/14356007.a07_067 |chapter=Chromium Compounds|isbn=3527306730}}</ref> Chromates and dichromates are used in [[chrome plating]] to protect metals from corrosion and to improve paint adhesion. Chromate and dichromate salts of [[heavy metals]], [[lanthanide]]s and [[alkaline earth metal]]s are only very slightly soluble in water and are thus used as pigments. The lead-containing pigment [[chrome yellow]] was used for a very long time before environmental regulations discouraged its use.<ref name="Yellow"/> When used as oxidizing agents or [[Titration|titrants]] in a [[redox]] [[chemical reaction]], chromates and dichromates convert into trivalent chromium, {{chem2|Cr(3+)}}, salts of which typically have a distinctively different blue-green color.<ref name=Ullmann/>