68
Er
Erbium
167
Erbium (Er)
LanthanidePeriod 6f-block-block
Erbium is a chemical element in the lanthanide series, with symbol Er and atomic number 68. A silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with other elements on Earth. As such, it is a rare earth element which is associated with several other rare elements in the mineral gadolinite from Ytterby in Sweden, where yttrium, ytterbium, and terbium were discovered.
Latin name: Erbium
Atomic Number
68
Atomic Mass
167 g/mol
Phase (STP)
Solid
Electron Config.
[Xe] 4f¹² 6s²
General
SymbolEr
Atomic Number68
Atomic Mass167 g/mol
CategoryLanthanide
Period6
Blockf-block
Electron Configuration[Xe] 4f¹² 6s²
Valence Electrons14
Coloursilvery-gray metallic
Appearancesilvery white
CAS NumberCAS7440-52-0
Physical Properties
Phase (STP)Solid
Density9.07 g/cm³
Melting Point1528.85°C · 2783.93°F · 1802.00 K
Boiling Point2867.85°C · 5194.13°F · 3141.00 K
Atomic Properties
Atomic Radius235 pm
Electronegativity1.24 Pauling
Ionization Energy589 kJ/mol
Oxidation States+3
Ion ChargeEr3+
Thermodynamic
Molar Heat28.12 J/(mol·K)
Crystal Structure
Crystal Structurehexagonal close-packed
Mechanical Properties
Mohs Hardness6
Nuclear & Hazards
Half-lifestable (Er-166, Er-167)
Abundance
In Universe0.00003%
In Sun0.000025%
In Earth's Crust0.0270%
In Meteorites0.00009999999999999999%
Discovery & History
Discovery Year1843
Discovered ByCarl Gustaf Mosander
Country of DiscoverySweden
Isotopes of Erbium
| Isotope | Abundance | Half-life | Decay |
|---|---|---|---|
| Er-162 | 0.139% | Stable | — |
| Er-164 | 1.601% | Stable | — |
| Er-166 | 33.503% | Stable | — |
| Er-167 | 22.869% | Stable | — |
| Er-168 | 26.978% | Stable | — |
| Er-170 | 14.91% | Stable | — |