Rhodium is a silver-white metallic element that is very reflective and resistant to corrosion. It is thought about the raremainder and also many handy precious steel in the human being — well over gold or silver. The name rhodium originates from the Greek word "rhodon," meaning increased, called for the rose-red shade of its salts.

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Just the facts

Atomic number (number of proloads in the nucleus): 45Atomic symbol (on the routine table of the elements): RhAtomic weight (average mass of the atom): 102.90550Density: 12.41 grams per cubic centimeterPhase at room temperature: SolidMelting point: 3,567 levels F (1,964 levels C)Boiling point: 6,683 levels F (3,695 degrees C)Number of isotopes (atoms of the exact same element through a various variety of neutrons):24 whose half-lives are known; one stableMany prevalent isotopes: One steady isotope Rh-103


Rhodium is among the of the 6 platinum team metals: platinum, palladium, rhodium, osmium, iridium and also ruthenium. It is also classified as a noble metal, interpretation that it does not react to oxygen quickly, acts as a wonderful catalyst and is resistant to corrosion and oxidation. Some common features of the platinum team metals incorporate high melting points, basic non-toxicity, and also resistance to wear, oxidation and also corrosion, according to Chemisattempt Libremessages.

Rhodium is the rarest of the platinum group, just occurring up to one part per 200 million in the Earth"s crust, according to Chemistry Libretexts. Rhodium has lower density and a greater melting allude than platinum. Rhodium it is unimpacted by air and also water approximately 1,112 levels Fahrenheit (600 degrees Celsius), according to Lenntech.



The primary usage for rhodium is in catalytic converters designed to clean car emissions. Rhodium — frequently together with palladium and/or platinum — accomplishes this by reducing nitrogen oxide in exhaust gas. Without rhodium catalysts, the air in our cities would be a lot worse as a result of vehicle exhausts.

Since rhodium is fairly brilliant and also resistant to tarnishing, it is supplied as a finish for jewelry, searchlights and mirrors. It is likewise alloyed via platinum for aircraft turbine engines. In the chemical market, rhodium is supplied as a catalyst in the making of nitric acid, acetic acid and also hydrogecountry reactions, according to the Royal Society of Chemisattempt (RSC).Other supplies for rhodium are coating optic fibers, crucibles, thermocouple elements and also headlight reflectors. Because it has actually a low electric resistance and is highly resistant to corrosion, it is provided as an electric contact product as well, according to RSC.

Rhodium is often alloyed through platinum and iridium to make an oxidation-resistant steel that deserve to stand against high temperatures. These alloys are supplied in furnace windings, pen nibs, phonograph needles, high-temperature thermocouple and resistance wires, electrodes for aircraft spark plugs, bearings and electrical contacts, according toLenntech.

Rhodium has no known biological use and no recognized usage for life procedures. While some compounds of rhodium are carcinogenic, there are practically no reported instances of humans being affected by this aspect in any kind of means. This might be because rhodium compounds are encountered so hardly ever. Test on plants have actually shown that it is the leastern toxic member of the platinum group of metals, according to Lenntechnology.

Although rhodium is primarily considered non-toxic, some of its compounds are toxic and also carcinogenic. Naturally developing rhodium consists of simply one steady isotope: Rh-103.

Who knew?

An alloy of rhodium-platinum is provided in heart pacemakers.Rhodium is resistant to a lot of acids.Rhodium steel is seldom used by itself and almost always as an alloy.All rhodium compounds are conveniently diminished or dewritten with heating to produce powdered (or sponge) metal.


Commercial rhodium is primarily obtained as a byproduct of copper and also nickel refining. In nature, rhodium deserve to take place unlinked or with other platinum minerals. It deserve to be uncovered in river sands in North and also South America and in copper-nickel sulfide ores in Ontario, Canada, according to the Royal Society of Chemisattempt.

Due to its rarity, the tiny industry dimension and the focused supply — South Africa alone produces approximately 80 percent of the world"s rhodium — prices are commonly volatile, according to Mining.com. For example, rhodium briefly got to $10,025 an ounce simply before the 2008 financial crisis hit, but then plunged 90 percent prior to the end of the year. In 2017, the price of rhodium even more than doubled, adding $1,000 an ounce given that hitting 12-year-lows mid-2016.

Storing the sun"s energy

Although rhodium appears to have actually discovered a solid market niche in cleaning car exhausts, many kind of new study tasks are showing that the valuable metal might host a lot even more potential, especially in its major role as a catalyst.

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In one such study, Swiss researchers at the Paul Scherrer Institute (PSI) and also the ETH Zuaffluent emerged a new chemical process that supplies the sun"s thermal energy to transform carbon dioxide and water right into high energy fuels. This chemical process entails a new material combicountry of cerium oxide and tiny quantities of rhodium as a catalyst. Their exploration is a significant action towards the chemical storage of solar energy (which has been a really tricky problem for scientists). Their brand-new findings are published in the journal Energy and Environpsychological Science.