Quick answerErbium (Er) is a lanthanide with atomic number 68 and an atomic mass of 167.26 (2023), in period 6. It was discovered by Carl Gustaf Mosander in 1843. It is used for fibre-optic amplifiers and lasers. Its electron configuration is [Xe] 4f12 6s2.
Erbium amplifies the light in fibre-optic cables, carrying internet signals across oceans without fading away.
Key facts
| Symbol | Er |
|---|---|
| Atomic number | 68 |
| Atomic mass | 167.26 (IUPAC standard atomic weight, 2023) |
| Category | lanthanide |
| Group | — (f-block element, no group number) |
| Period | 6 |
| Block | f-block |
| Electron configuration | [Xe] 4f12 6s2 |
| Discovered | Carl Gustaf Mosander, 1843 |
| Uses | fibre-optic amplifiers, lasers, pink glass colouring, nuclear reactor control, medical lasers |
Quick quiz
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Keep exploring
- Periodic table — all 118 elements
- Promethium (Pm) — another lanthanide, atomic number 61
- Samarium (Sm) — another lanthanide, atomic number 62
- Europium (Eu) — another lanthanide, atomic number 63
- Gadolinium (Gd) — another lanthanide, atomic number 64
- Terbium (Tb) — another lanthanide, atomic number 65
- Dysprosium (Dy) — another lanthanide, atomic number 66
- Holmium (Ho) — another lanthanide, atomic number 67
- Thulium (Tm) — another lanthanide, atomic number 69
- Ytterbium (Yb) — another lanthanide, atomic number 70
- Lutetium (Lu) — another lanthanide, atomic number 71
- All lanthanide elements — on the periodic table
Sources & last updated
- CIAAW — Standard Atomic Weights
- PubChem Periodic Table
- Wikipedia — Timeline of chemical element discoveries
Last updated: . Figures are shown with their year; where sources disagree, the value is left out rather than estimated.