Element 68
Erbium (Er)
Erbium (Er) is element 68 of the periodic table, a lanthanide in period 6 (f-block) with an atomic mass of 167.26 and is a solid at standard conditions.
At a glance
- Atomic number
- 68
- Symbol
- Er
- Atomic mass
- 167.26 u
- Category
- Lanthanides
- Period
- 6
- Block
- f-block
- Phase at STP
- solid
Electron structure
- Electron configuration
- 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f12 5s2 5p6 6s2
- Shorthand configuration
- [Xe] 4f12 6s2
- Electrons per shell
- 2, 8, 18, 30, 8, 2
- Oxidation states
- +2, +3
Physical properties
- Melting point
- 1802 K
- Boiling point
- 3141 K
- Density
- 9.066 g/cm3
- Phase
- solid
Atomic properties
- Electronegativity (Pauling)
- 1.24
- Atomic radius
- 226 pm
- Covalent radius
- 189 pm
- First ionization energy
- 589 kJ/mol
- Electron affinity
- 50 kJ/mol
Notable isotopes
| Isotope | Mass | Abundance | Stability |
|---|---|---|---|
| Er-166 | 165.9303 | 33.61% | Stable |
Common uses
- Fiber optic amplifiers
- Lasers
- Glass coloring
- Metallurgy
Discovery
- Year
- 1843
- Discovered by
- Carl Gustaf Mosander
- Country
- Sweden