Europium

Europium, 63Eu
Europium
Pronunciation/jʊˈrpiəm/ (yuu-ROH-pee-əm)
Appearancesilvery white, with a pale yellow tint;[1] but rarely seen without oxide discoloration
Standard atomic weight Ar°(Eu)
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
Groupf-block groups (no number)
Periodperiod 6
Block  f-block
Electron configuration[Xe] 4f7 6s2
Electrons per shell2, 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 (at 20° C)5.246 g/cm3[4]
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 statescommon: +2, +3
0[5]
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) (cI2)
Lattice constant
Body-centered cubic crystal structure for europium
a = 458.22 pm (at 20 °C)[4]
Thermal expansion26.3×10−6/K (at 20 °C)[4]
Thermal conductivityest. 13.9 W/(m⋅K)
Electrical resistivitypoly: 0.900 µΩ⋅m (at r.t.)
Magnetic orderingparamagnetic[6]
Molar magnetic susceptibility+34000.0×10−6 cm3/mol[7]
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)
Isotopes of europium
Main isotopes[8] Decay
abun­dance half-life (t1/2) mode pro­duct
150Eu synth 36.9 y β+ 150Sm
151Eu 47.8% 4.62×1018 y α 147Pm
152Eu synth 13.54 y ε 152Sm
β 152Gd
153Eu 52.2% stable
154Eu synth 8.59 y β 154Gd
155Eu synth 4.76 y β 155Gd
 Category: Europium
| references

Europium is a chemical element; it has symbol Eu and atomic number 63. Europium is a silvery-white metal of the lanthanide series that reacts readily with air to form a dark oxide coating. It is the most chemically reactive, least dense, and softest of the lanthanide elements. It is soft enough to be cut with a knife. Europium was isolated in 1901 and named after the continent of Europe.[9] Europium usually assumes the oxidation state +3, like other members of the lanthanide series, but compounds having oxidation state +2 are 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 the rare-earth elements on Earth.[10]

  1. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 112. ISBN 978-0-08-037941-8.
  2. ^ "Standard Atomic Weights: Europium". CIAAW. 1995.
  3. ^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
  4. ^ a b c Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.
  5. ^ Yttrium and all lanthanides except Ce and Pm have been observed in the oxidation state 0 in bis(1,3,5-tri-t-butylbenzene) complexes, see Cloke, F. Geoffrey N. (1993). "Zero Oxidation State Compounds of Scandium, Yttrium, and the Lanthanides". Chem. Soc. Rev. 22: 17–24. doi:10.1039/CS9932200017. and Arnold, Polly L.; Petrukhina, Marina A.; Bochenkov, Vladimir E.; Shabatina, Tatyana I.; Zagorskii, Vyacheslav V.; Cloke (2003-12-15). "Arene complexation of Sm, Eu, Tm and Yb atoms: a variable temperature spectroscopic investigation". Journal of Organometallic Chemistry. 688 (1–2): 49–55. doi:10.1016/j.jorganchem.2003.08.028.
  6. ^ Lide, D. R., ed. (2005). "Magnetic susceptibility of the elements and inorganic compounds". CRC Handbook of Chemistry and Physics (PDF) (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
  7. ^ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
  8. ^ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
  9. ^ "Periodic Table: Europium". Royal Society of Chemistry.
  10. ^ Stwertka, Albert. A Guide to the Elements, Oxford University Press, 1996, p. 156. ISBN 0-19-508083-1