Palladium

  • palladium, 46pd
    palladium (46 pd).jpg
    palladium
    pronunciationm/ (lay-dee-əm)
    appearancesilvery white
    standard atomic weight ar, std(pd)106.42(1)[1]
    palladium 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
    ni

    pd

    pt
    rhodiumpalladiumsilver
    atomic number (z)46
    groupgroup 10
    periodperiod 5
    blockd-block
    element category  transition metal
    electron configuration[kr] 4d10
    electrons per shell2, 8, 18, 18
    physical properties
    phase at stpsolid
    melting point1828.05 k ​(1554.9 °c, ​2830.82 °f)
    boiling point3236 k ​(2963 °c, ​5365 °f)
    density (near r.t.)12.023 g/cm3
    when liquid (at m.p.)10.38 g/cm3
    heat of fusion16.74 kj/mol
    heat of vaporization358 kj/mol
    molar heat capacity25.98 j/(mol·k)
    vapor pressure
    p (pa) 1 10 100 1 k 10 k 100 k
    at t (k) 1721 1897 2117 2395 2753 3234
    atomic properties
    oxidation states0, +1, +2, +3, +4 (a mildly basic oxide)
    electronegativitypauling scale: 2.20
    ionization energies
    • 1st: 804.4 kj/mol
    • 2nd: 1870 kj/mol
    • 3rd: 3177 kj/mol
    atomic radiusempirical: 137 pm
    covalent radius139±6 pm
    van der waals radius163 pm
    color lines in a spectral range
    spectral lines of palladium
    other properties
    natural occurrenceprimordial
    crystal structureface-centered cubic (fcc)
    face-centered cubic crystal structure for palladium
    speed of sound thin rod3070 m/s (at 20 °c)
    thermal expansion11.8 µm/(m·k) (at 25 °c)
    thermal conductivity71.8 w/(m·k)
    electrical resistivity105.4 nΩ·m (at 20 °c)
    magnetic orderingparamagnetic[2]
    magnetic susceptibility+567.4·10−6 cm3/mol (288 k)[3]
    young's modulus121 gpa
    shear modulus44 gpa
    bulk modulus180 gpa
    poisson ratio0.39
    mohs hardness4.75
    vickers hardness400–600 mpa
    brinell hardness320–610 mpa
    cas number7440-05-3
    history
    namingafter asteroid pallas, itself named after pallas athena
    discovery and first isolationwilliam hyde wollaston (1802)
    main isotopes of palladium
    iso­tope abun­dance half-life (t1/2) decay mode pro­duct
    100pd syn 3.63 d ε 100rh
    γ
    102pd 1.02% stable
    103pd syn 16.991 d ε 103rh
    104pd 11.14% stable
    105pd 22.33% stable
    106pd 27.33% stable
    107pd trace 6.5×106 y β 107ag
    108pd 26.46% stable
    110pd 11.72% stable
    | references

    palladium is a chemical element with the symbol pd and atomic number 46. it is a rare and lustrous silvery-white metal discovered in 1803 by the english chemist william hyde wollaston. he named it after the asteroid pallas, which was itself named after the epithet of the greek goddess athena, acquired by her when she slew pallas. palladium, platinum, rhodium, ruthenium, iridium and osmium form a group of elements referred to as the platinum group metals (pgms). they have similar chemical properties, but palladium has the lowest melting point and is the least dense of them.

    more than half the supply of palladium and its congener platinum is used in catalytic converters, which convert as much as 90% of the harmful gases in automobile exhaust (hydrocarbons, carbon monoxide, and nitrogen dioxide) into less noxious substances (nitrogen, carbon dioxide and water vapor). palladium is also used in electronics, dentistry, medicine, hydrogen purification, chemical applications, groundwater treatment, and jewelry. palladium is a key component of fuel cells, which react hydrogen with oxygen to produce electricity, heat, and water.

    ore deposits of palladium and other pgms are rare. the most extensive deposits have been found in the norite belt of the bushveld igneous complex covering the transvaal basin in south africa, the stillwater complex in montana, united states; the sudbury basin and thunder bay district of ontario, canada, and the norilsk complex in russia. recycling is also a source, mostly from scrapped catalytic converters. the numerous applications and limited supply sources result in considerable investment interest.

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

Palladium, 46Pd
Palladium (46 Pd).jpg
Palladium
Pronunciationm/ (LAY-dee-əm)
Appearancesilvery white
Standard atomic weight Ar, std(Pd)106.42(1)[1]
Palladium 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
Ni

Pd

Pt
rhodiumpalladiumsilver
Atomic number (Z)46
Groupgroup 10
Periodperiod 5
Blockd-block
Element category  Transition metal
Electron configuration[Kr] 4d10
Electrons per shell2, 8, 18, 18
Physical properties
Phase at STPsolid
Melting point1828.05 K ​(1554.9 °C, ​2830.82 °F)
Boiling point3236 K ​(2963 °C, ​5365 °F)
Density (near r.t.)12.023 g/cm3
when liquid (at m.p.)10.38 g/cm3
Heat of fusion16.74 kJ/mol
Heat of vaporization358 kJ/mol
Molar heat capacity25.98 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 1721 1897 2117 2395 2753 3234
Atomic properties
Oxidation states0, +1, +2, +3, +4 (a mildly basic oxide)
ElectronegativityPauling scale: 2.20
Ionization energies
  • 1st: 804.4 kJ/mol
  • 2nd: 1870 kJ/mol
  • 3rd: 3177 kJ/mol
Atomic radiusempirical: 137 pm
Covalent radius139±6 pm
Van der Waals radius163 pm
Color lines in a spectral range
Spectral lines of palladium
Other properties
Natural occurrenceprimordial
Crystal structureface-centered cubic (fcc)
Face-centered cubic crystal structure for palladium
Speed of sound thin rod3070 m/s (at 20 °C)
Thermal expansion11.8 µm/(m·K) (at 25 °C)
Thermal conductivity71.8 W/(m·K)
Electrical resistivity105.4 nΩ·m (at 20 °C)
Magnetic orderingparamagnetic[2]
Magnetic susceptibility+567.4·10−6 cm3/mol (288 K)[3]
Young's modulus121 GPa
Shear modulus44 GPa
Bulk modulus180 GPa
Poisson ratio0.39
Mohs hardness4.75
Vickers hardness400–600 MPa
Brinell hardness320–610 MPa
CAS Number7440-05-3
History
Namingafter asteroid Pallas, itself named after Pallas Athena
Discovery and first isolationWilliam Hyde Wollaston (1802)
Main isotopes of palladium
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct
100Pd syn 3.63 d ε 100Rh
γ
102Pd 1.02% stable
103Pd syn 16.991 d ε 103Rh
104Pd 11.14% stable
105Pd 22.33% stable
106Pd 27.33% stable
107Pd trace 6.5×106 y β 107Ag
108Pd 26.46% stable
110Pd 11.72% stable
| references

Palladium is a chemical element with the symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1803 by the English chemist William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired by her when she slew Pallas. Palladium, platinum, rhodium, ruthenium, iridium and osmium form a group of elements referred to as the platinum group metals (PGMs). They have similar chemical properties, but palladium has the lowest melting point and is the least dense of them.

More than half the supply of palladium and its congener platinum is used in catalytic converters, which convert as much as 90% of the harmful gases in automobile exhaust (hydrocarbons, carbon monoxide, and nitrogen dioxide) into less noxious substances (nitrogen, carbon dioxide and water vapor). Palladium is also used in electronics, dentistry, medicine, hydrogen purification, chemical applications, groundwater treatment, and jewelry. Palladium is a key component of fuel cells, which react hydrogen with oxygen to produce electricity, heat, and water.

Ore deposits of palladium and other PGMs are rare. The most extensive deposits have been found in the norite belt of the Bushveld Igneous Complex covering the Transvaal Basin in South Africa, the Stillwater Complex in Montana, United States; the Sudbury Basin and Thunder Bay District of Ontario, Canada, and the Norilsk Complex in Russia. Recycling is also a source, mostly from scrapped catalytic converters. The numerous applications and limited supply sources result in considerable investment interest.