Europium
Pronunciation | /j ʊəˈr oʊ p i ə m/ ​(yoor-OH-pee-əm)
Appearance | silvery white, with a pale yellow tint; but rarely seen without oxide discoloration
Standard atomic weight Ar, std(Eu) | 151.964(1)
Atomic number (Z) | 63
Group | group n/a
Period | period 6
Block | f-block
Element category | Lanthanide
Electron configuration | [Xe] 4f7 6s2
Electrons per shell | 2, 8, 18, 25, 8, 2
Phase at STP | solid
Melting point | 1099 K ​(826 °C, ​1519 °F)
Boiling point | 1802 K ​(1529 °C, ​2784 °F)
Density (near r.t.) | 5.264 g/cm3
when liquid (at m.p.) | 5.13 g/cm3
Heat of fusion | 9.21 kJ/mol
Heat of vaporization | 176 kJ/mol
Molar heat capacity | 27.66 J/(mol·K)
Oxidation states | +1, +2, +3 (a mildly basic oxide)
Electronegativity | Pauling scale: 1.2
Ionization energies | 1st: 547.1 kJ/mol 2nd: 1085 kJ/mol 3rd: 2404 kJ/mol
Atomic radius | empirical: 180 pm
Natural occurrence | primordial
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 ordering | paramagnetic
Magnetic susceptibility | +34,000.0·10−6 cm3/mol
Young's modulus | 18.2 GPa
Shear modulus | 7.9 GPa
Bulk modulus | 8.3 GPa
Poisson ratio | 0.152
Vickers hardness | 165–200 MPa
CAS Number | 7440-53-1
Naming | after Europe
Discovery and first isolation | Eugène-Anatole Demarçay (1896, 1901)