Europium

Europium is a chemical element wi the seembol Eu an atomic nummer 63. It is named efter the continent Europe. It is a moderately haird, sillery metal whilk readily oxidizes in air an watter. Bein a teepical member o the lanthanide series, europium uisually assumes the oxidation state +3, but the oxidation state +2 is common an aa: aw europium compoonds wi oxidation state +2 are slichtly reducing. Europium haes na signeeficant biological role an is relatively non-toxic compared tae ither hivy metals. Maist applications o europium exploit the phosphorescence o europium compoonds.

Europium, ₆₃Eu

Europium
Pronunciation	/j[unsupported input]oʊpiəm/ ​(yoor-OH-pee-əm)
Appearance	sillrry white, wi a pale yellsr tint;[1] but rarely seen without oxide discoloration
Standard atomic weight Ar, std(Eu)	7002151964000000000♠151.964(1)[2]
Europium in the periodic cairt
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 Airn Cobalt Nickel Capper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Siller (element) 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 Gowd Mercur (element) Thallium Leid (element) 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 Ununtrium Flerovium Ununpentium Livermorium Ununseptium Ununoctium – ↑ Eu ↓ Am samarium ← europium → gadolinium
Atomic nummer (Z)	63
Group	group n/a
Period	period 6
Block	f-block
Element category	Lanthanide
Electron confeeguration	[Xe] 4f7 6s2
Electrons per shell	2, 8, 18, 25, 8, 2
Pheesical properties
Phase at STP	solid
Meltin pynt	1099 K ​(826 °C, ​1519 °F)
Bylin pynt	1802 K ​(1529 °C, ​2784 °F)
Density (near r.t.)	5.264 g/cm3
when liquid (at m.p.)	5.13 g/cm3
Heat o fusion	9.21 kJ/mol
Heat o vapourisation	176 kJ/mol
Molar heat capacity	27.66 J/(mol·K)
Vapour pressur 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)
Electronegativity	Pauling scale: 1.2
Ionisation energies	1st: 547.1 kJ/mol 2nd: 1085 kJ/mol 3rd: 2404 kJ/mol
Atomic radius	empirical: 180 pm
Covalent radius	198±6 pm
Colour lines in a spectral range Spectral lines o europium
Ither properties
Naitural occurrence	primordial
Creestal structur	​bouk-centred cubic [[File:bouk-centred cubic|frameless|alt=Bouk-centred cubic creestal structur for europium|upright=0.23|Bouk-centred cubic creestal structur for europium]]
Thermal expansion	poly: 35.0 µm/(m·K) (at r.t.)
Thermal conductivity	est. 13.9 W/(m·K)
Electrical resistivity	poly: 0.900 µΩ·m (at r.t.)
Magnetic orderin	paramagnetic[3]
Magnetic susceptibility	+34,000.0·10−6 cm3/mol[4]
Young's modulus	18.2 GPa
Shear modulus	7.9 GPa
Bulk modulus	8.3 GPa
Poisson ratio	0.152
Vickers haurdness	165–200 MPa
CAS Nummer	7440-53-1
History
Namin	efter Europe
Diskivery an first isolation	Eugène-Anatole Demarçay (1896, 1901)
Main isotopes o europium
Iso­tope Abun­dance Hauf-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
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References

1. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth–Heinemann. p. 112. ISBN 0080379419.
2. Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.
3. 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.
4. Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.