Erbium (Er)
Erbium is element 68, a lanthanide in period 6 of the periodic table. At room temperature it is a solid.
Electron configuration [Xe] 4f12 6s2
Electrons per shell 2, 8, 18, 30, 8, 2
Erbium data
| Atomic number | 68 |
|---|---|
| Symbol | Er |
| Atomic mass | 167.259 u |
| Category | Lanthanide |
| Group | — (f-block) |
| Period | 6 |
| Block | f |
| State at 25 °C | solid |
| Melting point | 1770 K (1496.9 °C) |
| Boiling point | 3141 K (2867.9 °C) |
| Density | 9.066 g/cm³ |
| Electronegativity (Pauling) | 1.24 |
| Atomic radius | — |
| 1st ionization energy | 589 kJ/mol |
| Electron affinity | -50 kJ/mol |
| Oxidation states | +3 |
| Common ion charge | 3+ |
| Discovered | 1842 |
Orbital diagram
Each box is one orbital holding up to two electrons of opposite spin. Following Hund’s rule, electrons spread out singly across a subshell before pairing.
Work through erbium’s configuration and its ions →
Where erbium sits
Erbium belongs to the lanthanides. Its Pauling electronegativity of 1.24 is mid-range; see the electronegativity chart and periodic trends for context. To use its mass in a calculation, try the molar mass calculator.
Erbium FAQ
What is the electron configuration of erbium?
Erbium (Z = 68) has the configuration 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f12 6s2. In noble-gas shorthand that is [Xe] 4f12 6s2.
How many valence electrons does erbium have?
2 (2 in the outer s subshell).
What is the atomic mass of erbium?
The standard atomic weight of erbium is 167.259 u, so one mole weighs 167.259 g.
Is erbium a metal?
Yes. Erbium is a lanthanide.
What is the charge of a erbium ion?
Erbium most commonly forms Er3+.