Rhodium


 * Rhodium** a rare, silvery-white, hard, and chemically inert transition metal and a member of the platinum group. It has the chemical symbol **Rh** and atomic number 45. It is composed of only one isotope, 103Rh. Naturally occurring rhodium is found as the free metal, alloyed with similar metals, and never as a chemical compound. It is one of the rarest precious metals and one of the most costly. Rhodium is a so-called noble metal, resistant to corrosion, found in platinum- or nickel ores together with the other members of the platinum group metals. 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, produced after it reacted with the powerful acid mixture aqua regia.The element's major use (about 81% of world rhodium production) is as one of the catalysts in the three-way catalytic converters of automobiles. 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. White gold is often plated with a thin rhodium layer to improve its optical impression while sterling silver is often rhodium plated for tarnish resistance


 * Uses**
 * alloying agent to harden platinum and palladium. Such alloys are used for furnace windings, thermocouple elements, bushings for glass fibre production, electrodes for aircraft spark plugs, and laboratory crucibles
 * used as an electrical contact material as it has a low electrical resistance, a low and stable contact resistance, and is highly resistant to corrosion
 * plated rhodium produced by electroplating or evaporation is exceptionally hard and is used for optical instruments
 * used for jewellery
 * industrial catalyst
 * rhodium is used as part of the catalytic system in car catalytic converters, used to clean up exhaust gases to some extent


 * Date of Discovery:** 1803
 * Discoverer:** William Wollaston


 * Name Origin:** From the Greek word //rhodon// (rose)
 * Uses:** coatings
 * Obtained From:** by-product of nickel production


 * Symbol:** Rh **Atomic Number:** 45 **Atomic Mass:** 102.9055 amu **Melting Point:** 1966.0 °C (2239.15 K, 3570.8 °F) **Boiling Point:** 3727.0 °C (4000.15 K, 6740.6 °F) **Number of Protons/Electrons:** 45 **Number of Neutrons:** 58 **Classification:** Transition Metal **Crystal Structure:** Cubic **Density @ 293 K:** 12.41 g/cm3 **Color:** silverish

Atomic Structure

 * [[image:http://www.chemicalelements.com/bohr/b0045.gif width="309" height="307"]] ||  || **Number of Energy Levels:** 5
 * First Energy Level:** **Second Energy Level:** **Third Energy Level:** **Fourth Energy Level:** **Fifth Energy Level:** ||

Isotopes

 * ** Isotope ** || ** Half Life ** ||
 * Rh-101 || 3.3 years ||
 * Rh-101m || 4.35 days ||
 * Rh-102 || 2.9 years ||
 * Rh-102m || 207.0 days ||
 * Rh-103 || Stable ||
 * Rh-103m || 56.12 minutes ||
 * Rh-105 || 35.36 hours ||
 * Rh-105m || 40.0 seconds ||
 * Rh-106 || 29.9 seconds ||

Facts

 * Date of Discovery:** 1803 **Discoverer:** William Wollaston **Name Origin:** From the Greek word //rhodon// (rose) **Uses:** coatings **Obtained From:** by-product of nickel production