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Europium,  63Eu
Europium.jpg
Europium
Pronunciation/jʊəˈrpiəm/ (yoor-OH-pee-əm)
Appearancesilvery white, with a pale yellow tint; but rarely seen without oxide discoloration
Standard atomic weight Ar, std(Eu)151.964(1)
Europium 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


Eu

Am
samariumeuropiumgadolinium
Atomic number (Z)63
Groupgroup n/a
Periodperiod 6
Blockf-block
Element category  lanthanide
Electron configuration[Xe] 4f7 6s2
Electrons per shell
2, 8, 18, 25, 8, 2
Physical properties
Phase at STPsolid
Melting point1099 K ​(826 °C, ​1519 °F)
Boiling point1802 K ​(1529 °C, ​2784 °F)
Density (near r.t.)5.264 g/cm3
when liquid (at m.p.)5.13 g/cm3
Heat of fusion9.21 kJ/mol
Heat of vaporization176 kJ/mol
Molar heat capacity27.66 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 863 957 1072 1234 1452 1796
Atomic properties
Oxidation states+1, +2, +3 (a mildly basic oxide)
ElectronegativityPauling scale: 1.2
Ionization energies
  • 1st: 547.1 kJ/mol
  • 2nd: 1085 kJ/mol
  • 3rd: 2404 kJ/mol

Atomic radiusempirical: 180 pm
Covalent radius198±6 pm
Color lines in a spectral range
Spectral lines of europium
Other properties
Natural occurrenceprimordial
Crystal structurebody-centered cubic (bcc)
Body-centered cubic crystal structure for europium
Thermal expansionpoly: 35.0 µm/(m·K) (at r.t.)
Thermal conductivityest. 13.9 W/(m·K)
Electrical resistivitypoly: 0.900 µΩ·m (at r.t.)
Magnetic orderingparamagnetic
Magnetic susceptibility+34,000.0·10−6 cm3/mol
Young's modulus18.2 GPa
Shear modulus7.9 GPa
Bulk modulus8.3 GPa
Poisson ratio0.152
Vickers hardness165–200 MPa
CAS Number7440-53-1
History
Namingafter Europe
Discovery and first isolationEugène-Anatole Demarçay (1896, 1901)
Main isotopes of europium
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct
150Eu syn 36.9 y ε 150Sm
151Eu 47.8% 5×1018 y α 147Pm
152Eu syn 13.54 y ε 152Sm
β 152Gd
153Eu 52.2% stable
154Eu syn 8.59 y β 154Gd
155Eu syn 4.76 y β 155Gd

Europium is a chemical element with the symbol Eu and atomic number 63. Europium is the most reactive lanthanide by far, having to be stored under an inert fluid to protect it from atmospheric oxygen or moisture. Europium is also the softest lanthanide, as it can be dented with a finger nail and easily cut with a knife. When oxidation is removed a shiny-white metal is visible. Europium was isolated in 1901 and is named after the continent of Europe. Being a typical member of the lanthanide series, europium usually assumes the oxidation state +3, but the oxidation state +2 is also common. All europium compounds with oxidation state +2 are slightly reducing. Europium has no significant biological role and is relatively non-toxic compared to other heavy metals. Most applications of europium exploit the phosphorescence of europium compounds. Europium is one of the rarest of rare earth elements on Earth and among the least abundant elements in the universe; only about 5×10−8% of all matter in the universe is europium.

Characteristics