63EuEuropium151.964 u
Europium (Eu)
Europium is a lanthanide with atomic number 63, in period 6, in the f-block of the periodic table. Its atomic mass is 151.964 u and its electron configuration is [Xe] 4f⁷ 6s². Solid at 25 °C.
Key facts
| Atomic number | 63 |
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| Atomic mass | 151.964 u |
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| Category | Lanthanide |
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| Period | 6 |
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| Group | f-block, no group number |
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| Block | f |
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| Electron configuration | [Xe] 4f⁷ 6s² |
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| Electrons per shell | 2, 8, 18, 25, 8, 2 |
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| Electronegativity (Pauling) | --- |
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| Oxidation states | +2, +3common in bold |
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| State at 25 °C | Solid |
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| Melting point | 1095 K821.85 °C |
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| Boiling point | 1800 K1526.85 °C |
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| Density | 5.244 g/cm³ |
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Atomic properties
| First ionization energy | 5.67 eV |
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| Electron affinity | 50 kJ/mol |
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| Atomic radius | 199 pm |
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| Covalent radius | 198 pm |
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| Van der Waals radius | 233 pm |
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| Common ions | Eu³⁺, Eu²⁺ |
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| Protons, neutrons, electrons | 63, 89, 63 |
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Physical and thermal properties
| Molar volume | 28.97 cm³/mol |
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| Heat of fusion | 9.3 kJ/mol |
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| Heat of vaporization | 175 kJ/mol |
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| Specific heat | 182 J/(kg·K) |
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| Thermal conductivity | 14 W/(m·K) |
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| Thermal expansion | 3.5 × 10⁻⁵ K⁻¹ |
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| Mohs hardness | 3.07 |
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| Young’s modulus | 18 GPa |
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| Crystal structure | Body-centered cubic |
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| Magnetic type | Paramagnetic |
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Identification and history
| CAS number | 7440-53-1 |
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| Latin name | Europium |
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| Discovered by | Eugène-Anatole Demarçay · 1901 |
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| Named by | --- |
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Natural isotopes
| Isotope | Mass (u) | Abundance |
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| 151Eu | 150.919857 | 47.81 % |
| 153Eu | 152.921237 | 52.19 % |
Data checked against PubChem (NIH), IUPAC, the NIST Atomic Spectra Database and the IAEA (NUBASE and AME), the same data you see in the app.
A dash (---) means there is no reliable published measurement. The app never makes one up.
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Periodic Table