Chemical element · Atomic number 68
Erbium
Erbium in the periodic table: atomic number 68, electron configuration, atomic mass, physical data, oxidation states, media credit and visible sources.
Lanthanide
solid
167.26 u
Documented element sampleA documented sample of elemental erbium; the rare earth metal appears silvery-gray.
Image credit: James St. John
Auto-oriented, limited to 1600 × 1200 pixels and re-encoded as WebP; the subject was not altered.
Atomic classification
Shell occupancy
Erbium in the Bohr shell model
This shows the electron distribution of the neutral atom in a simplified shell model.
- K · n=1
- 2 electrons
- L · n=2
- 8 electrons
- M · n=3
- 18 electrons
- N · n=4
- 30 electrons
- O · n=5
- 8 electrons
- P · n=6
- 2 electrons
- Electron configuration
- [Xe]6s2 4f12
- Electrons per shell
- 2 · 8 · 18 · 30 · 8 · 2
- Group
- not reported
- Period
- 6
- Block
- F
- Element category
- Lanthanide
Physical and chemical properties
- Atomic mass
- 167.26 u
- Standard state
- solid
- Density
- 9.07 g/cm³
- Melting point
- 1,802 K
- Boiling point
- 3,141 K
- Electronegativity
- 1.24 (Pauling)
- First ionisation energy
- 6.108 eV
- Oxidation states
- +3
- Discovery
- 1843
Safety and periodic classification
Safety
Safe handling cannot be inferred from Erbium's position in the periodic table alone. Laboratory, classroom and disposal decisions must follow the documentation for the exact material and its safety data sheet.
Position and comparison
Erbium is in period 6 and the F block. Its direct neighbours by atomic number are Holmium and Thulium. The recorded Pauling electronegativity is 1.24. Periodic trends are compared only through the separately sourced neighbouring values.
Sources and scope
PubChem attributes element data to sources including IUPAC, NIST and IAEA. Quanta stores the referenced snapshot locally and leaves unknown values unavailable.
Where Erbium sits among the 118 elements
The table compares the reported values for Erbium with every other element that carries the same value in the snapshot. A rank is not a judgement, it is orientation: it says how unusual this value is across the periodic table.
| Value | Erbium | Position in the data set |
|---|---|---|
| Melting point | 1,802 K | Rank 27 of 103 elements with a reported value. Highest: Carbon. |
| Boiling point | 3,141 K | Rank 37 of 93 elements with a reported value. Highest: Rhenium. |
| Density | 9.07 g/cm³ | Rank 31 of 96 elements with a reported value. Highest: Osmium. |
| Electronegativity (Pauling) | 1.24 | Rank 75 of 95 elements with a reported value. Highest: Fluorine. |
| Ionisation energy | 6.108 eV | Rank 72 of 102 elements with a reported value. Highest: Helium. |
All values and ranks come from the PubChem Periodic Table snapshot, retrieved on 2026-07-15. Elements without a reported value are excluded, so the population differs per row.
The neighbours of Erbium in the periodic table
- Place in the table
- No group number, period 6, F block. Classified as lanthanide, solid at standard conditions.
- Direct neighbours
- Atomic number 68. Preceded by Holmium, followed by Thulium.
- Discovery
- Recorded in the snapshot as: 1843. Who, where and under what circumstances is not part of that record, so this page carries the sourced year and no discovery narrative.
- Oxidation states
- +3. They follow from the electron configuration [Xe]6s2 4f12 and indicate which compounds to expect.
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