Rhodium

45 102.9

Rhodium

Our Products Product Characteristics Application Areas Historical Background

Rhodium RdA-0,1,2
Producer	Principal applications	Product Form	Packaging
Krastsvetmet	Autocatalysts manufacturing industry Chemical industry Electrical industry Glass industry	Powder	Description: Plastic containers KT-2 Packing size: 301х241х130 mm

CHEMICAL COMPOSITION, %
Element	State standard 12342-81 for RdA-0	State standard 12342-81 for RdA-1	State standard 12342-81 for RdA-2
Rh min	99.97	99.95	99.90
Trace elements total (Pt, Pd, Ir, Ru)	0.010	0.020	0.030
Au	0.002	0.002	0.002
Ag	0.002	0.003	0.003
Pb	0.004	0.005	0.005
Fe	0.003	0.010	0.020
Si	0.004	0.005	0.005
Ba	0.004	0.005	0.005
Mg	0.001	0.003	0.003
Cu	0.003	0.005	0.020
Ni	0.001	0.002	0.005
Ti	0.004	0.005	0.010
Al	0.002	0.005	0.005
Sn	0.002	0.002	0.002
Loss on ignition	0.010	0.010	0.020

Physical and chemical characteristics
Latin name	Rhodium (Rh)
Group in Mendeleev’s periodic table	VIII
Atomic number	45
Atomic weight	102.9055
Density	12.41 g/sm³
Melting point	t 1,963 °С

Rhodium as a catalyst
Rhodium is essential for the nitric acid production: alloyed with platinum, it serves as an effective catalyst in the chemical reaction to produce nitric acid through air oxidation of ammonia. Rhodium is also used for the production of automobile exhaust catalysts as it can effectively decompose exhaust gases.

Jewellery
Rhodium electroplating is used to make jewellery shine as rhodium can reflect 80% of visible rays. It also helps jewellery resist scratches and tarnish and provides it with hypoallergenic properties. The plating may have a white, pink or goldish yellow tinge, or be tinted black to give a worn effect. Gemstone settings are usually rhodium-plated as well. In addition, platinum-rhodium alloys are used to produce filters for growing crystals of some precious minerals.

Scientific equipment
In the chemical industry, rhodium is used along with platinum to manufacture durable heat-resistant lab vessels: as the precious metal does not react with other elements, any substances may be mixed in rhodium flasks and test tubes. Rhodium is also employed in the production of scientific equipment, such as thermoelectric measuring devices and spectrometers. Rhodium detectors are used in nuclear reactors to measure neutron flux levels.

Glass production
Rhodium is widely applied in the glassmaking industry. Platinum-rhodium alloys are used to produce bushings for glass fibre (including optical fibre) and viscose manufacturing, as well as glass melting tanks for making extremely thin glass and quartz fibre (industrial glass threads, flat glass for computer screens).

Mirrors and reflectors
Thanks to its high reflectivity, rhodium is utilised for plating floodlight reflectors and technical mirrors in measuring tools. Dentistry employs rhodium-plated front surface mirrors reflecting light only once and providing clear images. Rhodium plating is also used in laser (e.g., hydrogen fluoride laser) mirrors exposed to high temperatures (heating).

Electronics
In electrical engineering, rhodium is used for plating connectors and contacts. Rhodium plating electrolytes (mainly sulphate, sulphamate and phosphate) serve to produce wear- and corrosion-resistant coatings. Rhodium alloyed with iridium and/or platinum is utilised to manufacture thermocouples for measuring high temperatures of up to 2,200 °C. The metal is also used as a solder for soldering wolfram and molybdenum, heating elements in resistance furnaces.

Rhodium was discovered in 1804 by the British scientist William Hyde-Woollaston, immediately after his discovery of palladium.

Woollaston dissolved virgin platinum in aqua regia, and then neutralized the excess acid with caustic soda. From the neutralised solution, he precipitated platinum with ammonium chloride, and palladium with mercury cyanide. The filtrate, processed with muriatic acid to get rid of the excess of mercury cyanide, was boiled dry. The residue, after having been treated with alcohol, turned out to be a dark red powder of double sodium rhodium salts of muriatic acid (chloride). The metal is then easily obtained by heating this powder in a stream of hydrogen.

Rhodium gets its name from the Greek “rhodon”, which means “rose”, on account of the pinkish red colour of its salts.

Safety Data sheet

Safety Data sheet PDF, 0.1 MB

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