Rhodium

It is a noble metal and a member of the platinum group.

The short list of chemically noble metals (those elements upon which almost all chemists agree) comprises ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), osmium (Os), iridium (Ir), platinum (Pt), and gold (Au).

It was discovered in 1803 by William Hyde Wollaston in one such ore, and named for the rose color of one of its chlorine compounds.

William Hyde Wollaston (6 August 1766 – 22 December 1828) was an English chemist and physicist who is famous for discovering the chemical elements palladium and rhodium.

Naturally occurring rhodium is usually found as free metal, as an alloy with similar metals, and rarely as a chemical compound in minerals such as bowieite and rhodplumsite.

Bowieite is a rhodium-iridium-platinum sulfide mineral (Rh,Ir,Pt) 2 S 3, found in platinum-alloy nuggets from Goodnews Bay, Alaska.

It is a noble metal and a member of the platinum group.

The six platinum-group metals are ruthenium, rhodium, palladium, osmium, iridium, and platinum.

Because rhodium metal is inert against corrosion and most aggressive chemicals, and because of its rarity, rhodium is usually alloyed with platinum or palladium and applied in high-temperature and corrosion-resistive coatings. This anomaly is also observed in the neighboring elements, niobium (41), ruthenium (44), and palladium (46).

Palladium, platinum, rhodium, ruthenium, iridium and osmium form a group of elements referred to as the platinum group metals (PGMs).

It is one of the rarest and most valuable precious metals.

Other precious metals include the platinum group metals: ruthenium, rhodium, palladium, osmium, iridium, and platinum, of which platinum is the most widely traded.

Rhodium is a chemical element with the symbol Rh and atomic number 45.

Naturally occurring rhodium is usually found as free metal, as an alloy with similar metals, and rarely as a chemical compound in minerals such as bowieite and rhodplumsite.

Rhodplumsite is a rare rhodium-lead sulfide mineral, chemical formula Rh 3 Pb 2 S 2.

It is a rare, silvery-white, hard, corrosion-resistant, and chemically inert transition metal.

The element's major use (approximately 80% of world rhodium production) is as one of the catalysts in the three-way catalytic converters in automobiles.

The precious metals inside the converter, including platinum, palladium, and rhodium, are extracted.

Rhodium detectors are used in nuclear reactors to measure the neutron flux level.

The element's major use (approximately 80% of world rhodium production) is as one of the catalysts in the three-way catalytic converters in automobiles.

Many catalytic processes, especially those used in organic synthesis, require "late transition metals", such as palladium, platinum, gold, ruthenium, rhodium, or iridium.

It was discovered in 1803 by William Hyde Wollaston in one such ore, and named for the rose color of one of its chlorine compounds.

Rhodium belongs to group 9 of the periodic table, but the configuration of electrons in the outermost shells is atypical for the group.

Members are cobalt (Co), rhodium (Rh), iridium (Ir) and meitnerium (Mt).

This anomaly is also observed in the neighboring elements, niobium (41), ruthenium (44), and palladium (46).

This anomaly is observed in the neighboring metals niobium (41), molybdenum (42), and rhodium (45).

The best-known rhodium-halogen compound is the Wilkinson's catalyst chlorotris(triphenylphosphine)rhodium(I).

Wilkinson's catalyst is the common name for chloridotris(triphenylphosphine)rhodium(I), a coordination complex of rhodium with the formula [RhCl(PPh 3 ) 3 ] (Ph = phenyl).

Rhodium(III) chloride, rhodium(IV) fluoride, rhodium(V) fluoride and rhodium(VI) fluoride are examples.

Rhodium hexafluoride, also rhodium(VI) fluoride, (RhF 6 ) is the inorganic compound of rhodium and fluorine.

This anomaly is also observed in the neighboring elements, niobium (41), ruthenium (44), and palladium (46).

(This can be observed in the neighborhood of ruthenium (44), rhodium (45), and palladium (46).)

Rhodium has numerous meta states, the most stable being 102m Rh (0.141 MeV) with a half-life of about 2.9 years and 101m Rh (0.157 MeV) with a half-life of 4.34 days (see isotopes of rhodium).

Naturally occurring rhodium ( 45 Rh) is composed of only one stable isotope, 103 Rh.

Diluted nitric acid dissolved all but palladium and rhodium.

In this process, anhydrous ammonia is oxidized to nitric oxide, in the presence of platinum or rhodium gauze catalyst at a high temperature of about 500 K and a pressure of 9 atm.

This catalyst is used in the hydroformylation or hydrogenation of alkenes.

Since the 1970s, most hydroformylation relies on catalysts based on rhodium.

The common oxidation state of rhodium is +3, but oxidation states from 0 to +6 are also observed.

The Rh−S bond is therefore extrapolated ionic against Allen electronegativities of rhodium and sulfur, yielding oxidation state +1 for rhodium:

Other uses of rhodium include asymmetric hydrogenation used to form drug precursors and the processes for the production of acetic acid.

In 1968, a rhodium-based catalyst (cis−[Rh(CO) 2 I 2 ] − ) was discovered that could operate efficiently at lower pressure with almost no by-products.

Rhodium metal does not normally form an oxide, even when heated.

Rhodium has both a higher melting point and lower density than platinum.