Editing Rhodium (section)

==History==
[[File:Wollaston William Hyde Jackson color.jpg|thumb|upright=0.8|left|[[William Hyde Wollaston]]]]

Rhodium (from {{langx|el|ῥόδον}} {{tlit|el|rhodon}}, meaning 'rose') was [[discovery of the chemical elements|discovered]] in 1803 by [[William Hyde Wollaston]],<ref>{{cite journal |title= On a New Metal, Found in Crude Platina |first=W. H. |last=Wollaston|author-link=William Hyde Wollaston |journal=[[Philosophical Transactions of the Royal Society of London]] |volume=94 |year=1804 |pages=419–430 |doi=10.1098/rstl.1804.0019| url = https://books.google.com/books?id=7AZGAAAAMAAJ&pg=PA419|doi-access=free }}</ref> soon after he discovered [[palladium]].<ref>{{cite journal|journal = Platinum Metals Review|url = http://www.platinummetalsreview.com/dynamic/article/view/47-4-175-183|title = Rhodium and Palladium – Events Surrounding Its Discovery|first = W. P. |last = Griffith|volume = 47|issue = 4|year = 2003|pages = 175–183| doi=10.1595/003214003X474175183 |doi-access = free}}</ref><ref>{{cite journal|title = On the Discovery of Palladium; With Observations on Other Substances Found with Platina|first = W. H.|last = Wollaston|author-link = William Hyde Wollaston|journal = [[Philosophical Transactions of the Royal Society of London]]|volume = 95|year = 1805|pages = 316–330|doi = 10.1098/rstl.1805.0024|doi-access = free}}</ref><ref name="contr">{{cite journal | doi = 10.1080/00033797800200431 | title = The Wollaston/Chenevix controversy over the elemental nature of palladium: A curious episode in the history of chemistry |year = 1978 | last1 = Usselman | first1 = Melvyn | journal = Annals of Science | volume = 35 | issue = 6 | pages = 551–579}}</ref> He used crude [[platinum]] ore presumably obtained from [[South America]].<ref>{{Cite book|author=Lide, David R.|title=CRC handbook of chemistry and physics: a ready-reference book of chemical and physical data|year=2004|publisher=CRC Press|location=Boca Raton|isbn=978-0-8493-0485-9|pages=[https://archive.org/details/crchandbookofche81lide/page/4 4–26]|url-access=registration|url=https://archive.org/details/crchandbookofche81lide/page/4}}</ref> His procedure dissolved the ore in [[aqua regia]] and neutralized the acid with [[sodium hydroxide]] (NaOH). He then precipitated the platinum as [[ammonium chloroplatinate]] by adding [[ammonium chloride]] ({{chem|NH|4|Cl}}). Most other metals like [[copper]], [[lead]], [[palladium]], and rhodium were precipitated with [[zinc]]. Diluted [[nitric acid]] dissolved all but palladium and rhodium. Of these, palladium dissolved in [[aqua regia]] but rhodium did not,<ref>{{Greenwood&Earnshaw2nd|page=1113}}</ref> and the rhodium was precipitated by the addition of [[sodium chloride]] as {{chem| Na|3|[RhCl|6|]·''n''H|2|O}}. After being washed with ethanol, the rose-red precipitate was reacted with zinc, which [[Displacement reaction|displaced]] the rhodium in the ionic compound and thereby released the rhodium as free metal.<ref name="griffith">{{cite journal |title=Bicentenary of Four Platinum Group Metals: Osmium and iridium – events surrounding their discoveries |author=Griffith, W. P. |journal=Platinum Metals Review |volume=47 |issue=4 |year=2003 |pages=175–183|doi=10.1595/003214003X474175183 |doi-access=free }}</ref>

For decades, the rare element had only minor applications; for example, by the turn of the century, rhodium-containing thermocouples were used to measure temperatures up to 1800&nbsp;°C.<ref>{{cite journal |year = 1904 | last1 = Hulett | first1 = G. A. | title = Volatilization of Platinum | last2 = Berger | first2 = H. W. | journal = Journal of the American Chemical Society | volume = 26 | issue = 11 | pages = 1512–1515 | doi=10.1021/ja02001a012| bibcode = 1904JAChS..26.1512H | url = https://zenodo.org/record/1428894 |via= Zenodo |url-status=live |archive-url=https://web.archive.org/web/20240124003101/https://zenodo.org/records/1428894/files/article.pdf?download=1 |archive-date= Jan 24, 2024 }}</ref><ref>{{cite book | chapter = Platinum Type | isbn = 978-0-8031-1466-1 | chapter-url = https://books.google.com/books?id=Pos-MXDWb6MC&pg=PA63 | title = Manual on the use of thermocouples in temperature measurement | series = ASTM Special Technical Publication | publisher = ASTM International | author1 = ((ASTM Committee E.2.0. on Temperature Measurement)) | year = 1993 | bibcode = 1981mutt.book.....B }}{{Dead link|date=June 2024 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> They have exceptionally good stability in the temperature range of 1300 to 1800&nbsp;°C.<ref>J. V. Pearce, F. Edler, C. J. Elliott, A. Greenen, P. M. Harris, C. G.  Izquierdo, Y. G. Kim, M. J. Martin, I. M. Smith, D. Tucker and R. I. Veitcheva, A systematic investigation of the thermoelectric stability of Pt-Rh thermocouples between 1300&nbsp;°C and 1500&nbsp;°C, METROLOGIA, 2018, Volume: 55 Issue: 4 Pages: 558-567</ref>

The first major application was electroplating for decorative uses and as corrosion-resistant coating.<ref>{{cite journal | last = Kushner | first = Joseph B. | journal = Metals and Alloys | pages = 137–140 |year = 1940 | title = Modern rhodium plating | volume = 11 }}</ref> The introduction of the three-way [[catalytic converter]] by [[Volvo]] in 1976 increased the demand for rhodium. The previous catalytic converters used platinum or palladium, while the three-way catalytic converter used rhodium to reduce the amount of [[NOx|NO<sub>x</sub>]] in the exhaust.<ref>{{cite journal | doi = 10.1016/S0959-6526(00)00082-2 | title = Life cycle assessment of a catalytic converter for passenger cars |year = 2001 | last1 = Amatayakul | first1 = W. | journal = Journal of Cleaner Production | volume = 9 | issue = 5 | pages = 395–403 | last2 = Ramnäs | first2 = Olle| bibcode = 2001JCPro...9..395A }}</ref><ref>{{cite journal | doi = 10.1016/S0926-860X(01)00818-3 | title = Automobile exhaust catalysts |year = 2001 | last1 = Heck | first1 = R. | journal = Applied Catalysis A: General | volume = 221 | issue = 1–2 | pages = 443–457 | last2 = Farrauto | first2 = Robert J.| bibcode = 2001AppCA.221..443H }}</ref><ref>{{cite journal | doi =  10.1016/S1385-8947(00)00365-X | title = The application of monoliths for gas phase catalytic reactions |year = 2001 | last1 = Heck | first1 = R. | journal = Chemical Engineering Journal | volume = 82 | issue = 1–3 | pages = 149–156 | last2 = Gulati | first2 = Suresh | last3 = Farrauto | first3 = Robert J.| bibcode = 2001ChEnJ..82..149H }}</ref>