Rhodium, one of the world’s rarest and most valuable precious metals, has played a fascinating yet often overlooked role in human technological advancement over the past two centuries. From its serendipitous discovery in 1803 to its current position as an indispensable component in automotive emissions control and industrial catalysis, rhodium’s journey reflects humanity’s evolving relationship with chemistry, environmental consciousness, and technological innovation. This silvery-white metal, whose name derives from the Greek word “rhodon” meaning rose, has transcended its initial status as a scientific curiosity to become a critical element in modern industry, commanding prices that frequently exceed those of gold and platinum. Understanding rhodium’s historical trajectory provides valuable insights into the intersection of scientific discovery, industrial development, and environmental stewardship that continues to shape our world today.

Read about the six platinum group metals – Iridium, Osmium, Palladium, Platinum, Rhodium, and Ruthenium – as a group (PGMs) here. Find out about the other critical raw materials (CRMs) here. The complete history of platinum can be found here. Find the complete history of all platinum group metals here.

A History Of Rhodium

The story of rhodium encompasses over two centuries of scientific discovery, industrial innovation, and technological advancement. From its extraction from platinum ore in a London laboratory to its current role as an essential catalyst in reducing global automotive emissions, rhodium has evolved from a chemical curiosity to one of the most strategically important metals in modern industry. Its extreme rarity, unique chemical properties, and irreplaceable role in environmental protection have made it one of the most valuable substances on Earth, with its history reflecting broader patterns of scientific progress, industrial development, and growing environmental awareness.

Chronology

• 1803 – William Hyde Wollaston discovers rhodium while working with platinum ore in London, extracting it from residues obtained from South American platinum ore; names the new element after the Greek word “rhodon” meaning rose, due to the distinctive rose-red color of its chlorine compounds [1, 2, 3, 8, 9, 10]
• 1804 – Wollaston formally announces the discovery of rhodium in a paper titled “On a New Metal, found in Crude Platina” read before the Royal Society on June 24, presenting rose-red crystals of sodium rhodium chloride (Na3RhCl6·nH2O) [4, 5, 6, 7]
• 1805 – Wollaston begins commercial production of pure platinum using his secret powder metallurgy process, with rhodium recovered as a valuable byproduct [10]
• 1821 – Wollaston and his assistant John Dowse complete processing of approximately 47,000 Troy ounces of platinum ore, having recovered 255 Troy ounces of rhodium and 302 Troy ounces of palladium since 1803 [10]
• 1900 – Rhodium-containing thermocouples come into use for measuring temperatures up to 1800°C, marking one of the first practical applications of the metal [10]
• 1965 – Geoffrey Wilkinson publishes his first papers on rhodium catalysts at Imperial College London, describing the synthesis of chloridotris(triphenylphosphine)rhodium(I), later known as Wilkinson’s catalyst [11, 12]
• 1968 – D. Evans, J.A. Osborn, and G. Wilkinson describe the use of rhodium complex catalysts for hydroformylation of alkenes, revolutionizing industrial organic synthesis [11, 13]
• 1970s – Rhodium begins widespread use in three-way catalytic converters for automobiles, becoming essential for reducing nitrogen oxide emissions [5, 10, 14]
• 1973 – Geoffrey Wilkinson wins the Nobel Prize in Chemistry, with his work on rhodium catalysts recognized as a major contribution to organometallic chemistry [12, 15]
• 1976 – Volvo introduces the three-way catalytic converter using rhodium, platinum, and palladium, becoming the first automaker to implement this technology for California emission standards; rhodium-based self-powered neutron detectors begin deployment in nuclear reactors for monitoring neutron flux levels [10, 11, 14, 16, 17, 18, 19]
• 1977 – California implements the world’s strictest emission legislation requiring hydrocarbons at 0.41 g/mile, carbon monoxide at 9.0 g/mile, and nitrogen oxides at 1.5 g/mile, driving rhodium demand [20]
• 1979 – Paul McCartney receives a rhodium-plated disc from the Guinness Book of Records for being the “most honoured man in music,” highlighting rhodium’s use for exceptional honors [10, 21, 22, 23]
• 1980s – Low-pressure oxo processes using rhodium catalysts become dominant for hydroformylation reactions in the chemical industry [24, 25]
• 1984 – Ruhrchemie/Rhone-Poulenc builds a plant in Oberhausen using water-soluble rhodium catalysts for propene hydroformylation, with production capacity reaching 500,000 t/a butanal by 1998 [25]
• 2003 – Bicentennial of rhodium’s discovery is marked, commemorating 200 years since Wollaston first isolated the element [5]
• 2008 – Rhodium price reaches historic peak of $10,025 per ounce before crashing 90% by year-end due to the global financial crisis; net demand for rhodium in automotive converters reaches 84% of world usage, establishing automobiles as the dominant consumer [10, 14, 26, 27, 28]
• 2012 – Global rhodium consumption reaches 30,000 kg, with 81% (24,300 kg) used in automotive applications and 8,060 kg recovered from recycling [14]
• 2015 – Volkswagen emissions scandal (“Dieselgate”) shifts demand from diesel to gasoline vehicles, increasing rhodium requirements for gasoline catalytic converters [27, 29]
• 2016 – Average rhodium price drops to $800 USD per Troy ounce, leading to decreased mining activity [27]
• 2017 – Rhodium prices begin sustained increase following Dieselgate scandal as gasoline vehicle production rises [27]
• 2018 – Approximately 84% of rhodium production (24.07 tons) is consumed by automotive catalytic converters [30]
• 2019 – Global mined supply of rhodium reaches over 750,000 ounces with recycled supply at 315,000 ounces, creating a deficit of approximately 50,000 ounces [31]
• 2020 – Demand for rhodium totals 31.2 tons with 90% consumed by the automotive catalyst industry, while 7.3 tons are recovered from recycling [32]
• 2021 – Rhodium price approaches $30,000 USD per ounce in early 2021 before settling to $14,000 USD per ounce by year-end; South African PGM miners report rhodium contributing 25-40% of revenue despite representing only 6-8% of production volume [27, 31, 33]
• 2022 – Over 31 metric tons of rhodium used in automotive applications as stricter emissions standards in China and Europe drive demand [34]
• 2023 – Rhodium stabilizes around $4,110 per troy ounce after dropping 66.53% from beginning of year highs [35]
• 2024 – Global rhodium market valued at USD 2.44 billion with projections to reach USD 3.66 billion by 2033 [36]
• 2025 – Annual global rhodium production remains constrained at approximately 30 metric tons, with 85% sourced from South Africa [34, 37, 31]

Final Thoughts

The history of rhodium reveals a remarkable transformation from laboratory curiosity to industrial necessity, driven by humanity’s evolving environmental consciousness and technological capabilities. What began as William Hyde Wollaston’s patient extraction of rose-colored crystals from platinum ore has evolved into a global industry vital to air quality and human health. The metal’s journey through the centuries – from early thermocouple applications to its revolutionary role in catalytic chemistry and emissions control – demonstrates how scientific discovery can profoundly impact society in ways unimaginable to its discoverers. As we face mounting environmental challenges and the transition to cleaner technologies, rhodium’s story serves as both an inspiration and a cautionary tale about the complex relationships between rare resources, technological progress, and sustainable development. While electric vehicles may eventually reduce rhodium’s dominance in automotive applications, its unique catalytic properties ensure it will remain essential to numerous industrial processes. The continuing scarcity of rhodium, combined with its irreplaceable role in protecting our atmosphere, guarantees that this remarkable element will continue to shape technological innovation and environmental policy for generations to come.

Thanks for reading!

References

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[2] When was rhodium discovered? Fascinating Story of Rhodium! – https://knollmont.com/metals/when-was-rhodium-discovered/

[3] William Hyde Wollaston – Wikipedia – https://en.wikipedia.org/wiki/William_Hyde_Wollaston

[4] Two men, two centuries, four metals | Feature | Chemistry World – https://www.chemistryworld.com/features/two-men-two-centuries-four-metals/3004876.article

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[8] William Hyde Wollaston, a great unknown, discovered palladium and rhodium – Rincón educativo – https://rinconeducativo.org/en/recursos-educativos/william-hyde-wollaston-discovered-palladium-and-rhodium/

[9] Wollaston’s Work on Metallurgy | EBSCO Research Starters – https://www.ebsco.com/research-starters/history/wollastons-work-metallurgy

[10] Rhodium – Wikipedia – https://en.wikipedia.org/wiki/Rhodium

[11] Hydroformylation of alkenes by use of rhodium complex catalysts – Journal of the Chemical Society A – https://pubs.rsc.org/en/content/articlelanding/1968/j1/j19680003133

[12] Wilkinson’s catalyst – American Chemical Society – https://www.acs.org/molecule-of-the-week/archive/w/wilkinsons-catalyst.html

[13] Mild hydroformylation of olefins using rhodium catalysts – Chemical Communications (London) – https://pubs.rsc.org/en/content/articlelanding/1965/c1/c19650000017

[14] The History of the Catalytic Converter: From Invention to Mandate – https://catalyticconvertersolutions.com/the-history-of-the-catalytic-converter

[15] Wilkinson’s catalyst – Wikipedia – https://en.wikipedia.org/wiki/Wilkinson’s_catalyst

[16] This week in 1976: Volvo introduces three-way catalytic converter – https://www.autoweek.com/car-life/a1927611/week-1976-volvo-introduces-three-way-catalytic-converter/

[17] Simulation study of a rhodium self-powered neutron detector – ScienceDirect – https://www.sciencedirect.com/science/article/pii/S0168900223010707

[18] Rhodium Emitter – Rhodium-based SPND – https://www.nuclear-power.com/nuclear-power-plant/nuclear-reactor/nuclear-instrumentation/incore-nuclear-instrumentation/rhodium-emitter-rhodium-based-spnd/

[19] Rhodium in-core detector sensitivity depletion. Interim report (Technical Report) | OSTI.GOV – https://www.osti.gov/biblio/5426151

[20] 30 years of Volvo’s revolutionary Lambda sensor – Volvo Cars Global Media Newsroom – https://www.media.volvocars.com/global/en-gb/media/pressreleases/5124

[21] Paul McCartney awarded “most successful songwriter of all time” by Guinness World Records • The Paul McCartney Project – https://www.the-paulmccartney-project.com/1979/10/paul-mccartney-awarded-most-successful-songwriter-of-all-time-by-guinness-world-records/

[22] Paul McCartney inducted into The Guinness Book of Records Hall of Fame • The Paul McCartney Project – https://www.the-paulmccartney-project.com/1986/05/paul-mccartney-inducted-into-the-guinness-book-of-records-hall-of-fame/

[23] Paul McCartney receives Guinness award 40 years ago #OnThisDay #OTD (Oct 24 1979) – RetroNewser – https://retronewser.com/2019/10/24/paul-mccartney-receives-guinness-award/

[24] Hydroformylation | ChemTexts – https://link.springer.com/article/10.1007/s40828-021-00154-x

[25] Hydroformylation – Wikipedia – https://en.wikipedia.org/wiki/Hydroformylation

[26] Palladium price peaks at new record high, rhodium roaring – MINING.COM – https://www.mining.com/palladium-price-peaks-at-new-record-high-rhodium-roaring/

[27] Rhodium and the Rhodium Price – https://www.dailymetalprice.com/rhodium.html

[28] Rhodium price fluctuation in the period 2000-2010 | Download Scientific Diagram – https://www.researchgate.net/figure/Rhodium-price-fluctuation-in-the-period-2000-2010-1_fig2_284625081

[29] The five most expensive metals and where they are mined – https://www.mining-technology.com/features/five-most-expensive-metals-and-where-they-are-mined/

[30] Recent Developments on Processes for Recovery of Rhodium Metal from Spent Catalysts – https://www.mdpi.com/2073-4344/12/11/1415

[31] What is Rhodium and Why is it So Valuable? – New Age Metals Inc. – https://newagemetals.com/what-is-rhodium-and-why-is-it-so-valuable/

[32] Are There Precious Metals in Catalytic Converters? – https://www.thermofisher.com/blog/metals/platinum-group-metal-recovery-from-spent-catalytic-converters-using-xrf/

[33] Rhodium on the rise – Mining Technology – https://www.mining-technology.com/features/rhodium-on-the-rise/

[34] Rhodium Price – Historical Chart – 2025 Forecast – How to Buy – https://strategicmetalsinvest.com/rhodium-prices/

[35] Rhodium: The World’s Priciest Metal Explained – https://www.theassay.com/articles/analysis/rhodium-the-worlds-priciest-metal-explained/

[36] Rhodium Market Size & Forecast | Analysis Report, 2025-2033 – https://www.businessresearchinsights.com/market-reports/rhodium-market-107322

[37] South Africa | SFA (Oxford) – https://www.sfa-oxford.com/knowledge-and-insights/platinum-group-metals/pgm-mining/south-africa/