Erbium (symbol Er, atomic number 68) is a rare-earth metal used to amplify signals in fibre-optic cables. It is classified as a lanthanide and sits in the lanthanide series (f-block), period 6 of the periodic table.
Overview
Erbium is the chemical element with atomic number 68 and the symbol Er. With a standard atomic weight of 167.26, it is a lanthanide. In the periodic table it occupies the lanthanide series (f-block) and period 6, and under standard conditions it is normally a solid. Erbium is a rare-earth metal used to amplify signals in fibre-optic cables.
Atomic structure
An atom of Erbium has 68 protons in its nucleus and, when neutral, 68 electrons arranged in the configuration [Xe] 4f12 6s2. Its standard atomic weight of 167.26 reflects the natural mix of its stable isotopes.
Discovery and place in the table
Erbium was discovered in 1843 by Carl Gustaf Mosander. It follows Holmium (Ho) and precedes Thulium (Tm) in order of atomic number.
| Atomic number | 68 |
|---|---|
| Symbol | Er |
| Atomic mass | 167.26 |
| Category | Lanthanide |
| Group | — |
| Period | 6 |
| Electron configuration | [Xe] 4f12 6s2 |
| Phase at STP | Solid |
| Discovered | 1843 (Carl Gustaf Mosander) |