Rhodium

  • rhodium, 45rh
    rhodium powder pressed melted.jpg
    rhodium
    pronunciationm/ (roh-dee-əm)
    appearancesilvery white metallic
    standard atomic weight ar, std(rh)102.90549(2)[1]
    rhodium in the periodic table
    hydrogen helium
    lithium beryllium boron carbon nitrogen oxygen fluorine neon
    sodium magnesium aluminium silicon phosphorus sulfur chlorine argon
    potassium calcium scandium titanium vanadium chromium manganese iron cobalt nickel copper zinc gallium germanium arsenic selenium bromine krypton
    rubidium strontium yttrium zirconium niobium molybdenum technetium ruthenium rhodium palladium silver cadmium indium tin antimony tellurium iodine xenon
    caesium barium lanthanum cerium praseodymium neodymium promethium samarium europium gadolinium terbium dysprosium holmium erbium thulium ytterbium lutetium hafnium tantalum tungsten rhenium osmium iridium platinum gold mercury (element) thallium lead bismuth polonium astatine radon
    francium radium actinium thorium protactinium uranium neptunium plutonium americium curium berkelium californium einsteinium fermium mendelevium nobelium lawrencium rutherfordium dubnium seaborgium bohrium hassium meitnerium darmstadtium roentgenium copernicium nihonium flerovium moscovium livermorium tennessine oganesson
    co

    rh

    ir
    rutheniumrhodiumpalladium
    atomic number (z)45
    groupgroup 9
    periodperiod 5
    blockd-block
    element category  transition metal
    electron configuration[kr] 4d8 5s1
    electrons per shell2, 8, 18, 16, 1
    physical properties
    phase at stpsolid
    melting point2237 k ​(1964 °c, ​3567 °f)
    boiling point3968 k ​(3695 °c, ​6683 °f)
    density (near r.t.)12.41 g/cm3
    when liquid (at m.p.)10.7 g/cm3
    heat of fusion26.59 kj/mol
    heat of vaporization493 kj/mol
    molar heat capacity24.98 j/(mol·k)
    vapor pressure
    p (pa) 1 10 100 1 k 10 k 100 k
    at t (k) 2288 2496 2749 3063 3405 3997
    atomic properties
    oxidation states−3, −1, 0, +1,[2] +2, +3, +4, +5, +6 (an amphoteric oxide)
    electronegativitypauling scale: 2.28
    ionization energies
    • 1st: 719.7 kj/mol
    • 2nd: 1740 kj/mol
    • 3rd: 2997 kj/mol
    atomic radiusempirical: 134 pm
    covalent radius142±7 pm
    color lines in a spectral range
    spectral lines of rhodium
    other properties
    natural occurrenceprimordial
    crystal structureface-centered cubic (fcc)
    face-centered cubic crystal structure for rhodium
    speed of sound thin rod4700 m/s (at 20 °c)
    thermal expansion8.2 µm/(m·k) (at 25 °c)
    thermal conductivity150 w/(m·k)
    electrical resistivity43.3 nΩ·m (at 0 °c)
    magnetic orderingparamagnetic[3]
    magnetic susceptibility+111.0·10−6 cm3/mol (298 k)[4]
    young's modulus380 gpa
    shear modulus150 gpa
    bulk modulus275 gpa
    poisson ratio0.26
    mohs hardness6.0
    vickers hardness1100–8000 mpa
    brinell hardness980–1350 mpa
    cas number7440-16-6
    history
    discovery and first isolationwilliam hyde wollaston (1804)
    main isotopes of rhodium
    iso­tope abun­dance half-life (t1/2) decay mode pro­duct
    99rh syn 16.1 d ε 99ru
    γ
    101mrh syn 4.34 d ε 101ru
    it 101rh
    γ
    101rh syn 3.3 y ε 101ru
    γ
    102mrh syn 3.7 y ε 102ru
    γ
    102rh syn 207 d ε 102ru
    β+ 102ru
    β 102pd
    γ
    103rh 100% stable
    105rh syn 35.36 h β 105pd
    γ
    category category: rhodium
    | references

    rhodium is a chemical element with the symbol rh and atomic number 45. it is a rare, silvery-white, hard, corrosion-resistant, and chemically inert transition metal. it is a noble metal and a member of the platinum group. it has only one naturally occurring isotope, 103rh. 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. it is one of the rarest and most valuable precious metals.

    rhodium is 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.

    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. 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 appearance while sterling silver is often rhodium-plated for tarnish resistance. rhodium is sometimes used to cure silicones; a two-part silicone in which one part containing a silicon hydride and the other containing a vinyl-terminated silicone are mixed. one of these liquids contains a rhodium complex.[5]

    rhodium detectors are used in nuclear reactors to measure the neutron flux level. other uses of rhodium include asymmetric hydrogenation used to form drug precursors and the processes for the production of acetic acid.

  • history
  • characteristics
  • occurrence
  • applications
  • precautions
  • see also
  • references
  • external links

Rhodium, 45Rh
Rhodium powder pressed melted.jpg
Rhodium
Pronunciationm/ (ROH-dee-əm)
Appearancesilvery white metallic
Standard atomic weight Ar, std(Rh)102.90549(2)[1]
Rhodium in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
Co

Rh

Ir
rutheniumrhodiumpalladium
Atomic number (Z)45
Groupgroup 9
Periodperiod 5
Blockd-block
Element category  Transition metal
Electron configuration[Kr] 4d8 5s1
Electrons per shell2, 8, 18, 16, 1
Physical properties
Phase at STPsolid
Melting point2237 K ​(1964 °C, ​3567 °F)
Boiling point3968 K ​(3695 °C, ​6683 °F)
Density (near r.t.)12.41 g/cm3
when liquid (at m.p.)10.7 g/cm3
Heat of fusion26.59 kJ/mol
Heat of vaporization493 kJ/mol
Molar heat capacity24.98 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 2288 2496 2749 3063 3405 3997
Atomic properties
Oxidation states−3, −1, 0, +1,[2] +2, +3, +4, +5, +6 (an amphoteric oxide)
ElectronegativityPauling scale: 2.28
Ionization energies
  • 1st: 719.7 kJ/mol
  • 2nd: 1740 kJ/mol
  • 3rd: 2997 kJ/mol
Atomic radiusempirical: 134 pm
Covalent radius142±7 pm
Color lines in a spectral range
Spectral lines of rhodium
Other properties
Natural occurrenceprimordial
Crystal structureface-centered cubic (fcc)
Face-centered cubic crystal structure for rhodium
Speed of sound thin rod4700 m/s (at 20 °C)
Thermal expansion8.2 µm/(m·K) (at 25 °C)
Thermal conductivity150 W/(m·K)
Electrical resistivity43.3 nΩ·m (at 0 °C)
Magnetic orderingparamagnetic[3]
Magnetic susceptibility+111.0·10−6 cm3/mol (298 K)[4]
Young's modulus380 GPa
Shear modulus150 GPa
Bulk modulus275 GPa
Poisson ratio0.26
Mohs hardness6.0
Vickers hardness1100–8000 MPa
Brinell hardness980–1350 MPa
CAS Number7440-16-6
History
Discovery and first isolationWilliam Hyde Wollaston (1804)
Main isotopes of rhodium
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct
99Rh syn 16.1 d ε 99Ru
γ
101mRh syn 4.34 d ε 101Ru
IT 101Rh
γ
101Rh syn 3.3 y ε 101Ru
γ
102mRh syn 3.7 y ε 102Ru
γ
102Rh syn 207 d ε 102Ru
β+ 102Ru
β 102Pd
γ
103Rh 100% stable
105Rh syn 35.36 h β 105Pd
γ
Category Category: Rhodium
| references

Rhodium is a chemical element with the symbol Rh and atomic number 45. It is a rare, silvery-white, hard, corrosion-resistant, and chemically inert transition metal. It is a noble metal and a member of the platinum group. It has only one naturally occurring isotope, 103Rh. 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. It is one of the rarest and most valuable precious metals.

Rhodium is 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.

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. 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 appearance while sterling silver is often rhodium-plated for tarnish resistance. Rhodium is sometimes used to cure silicones; a two-part silicone in which one part containing a silicon hydride and the other containing a vinyl-terminated silicone are mixed. One of these liquids contains a rhodium complex.[5]

Rhodium detectors are used in nuclear reactors to measure the neutron flux level. Other uses of rhodium include asymmetric hydrogenation used to form drug precursors and the processes for the production of acetic acid.