Erbium (Er)
Stable isotopes of erbium available from ISOFLEX
Isotope | Z(p) | N(n) | Atomic Mass | Natural Abundance | Enrichment Level | Chemical Form |
Er-162 | 68 | 94 | 161.928775 | 0.14% | 28.20-39.20% | Oxide |
Er-164 | 68 | 96 | 163.929197 | 1.61% | 51.30-75.30% | Oxide |
Er-166 | 68 | 98 | 165.930290 | 33.60% | 94.70-98.10% | Oxide |
Er-167 | 68 | 99 | 166.932046 | 22.95% | 95.30-96.30% | Oxide |
Er-168 | 68 | 100 | 167.932368 | 26.80% | >98.00% | Oxide |
Er-170 | 68 | 102 | 169.935461 | 14.90% | 97.70-98.20% | Oxide |
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Erbium was discovered in 1842 by Carl G. Mosander. It is named for the village of Ytterby, near Vaxholm, Sweden.
A soft, malleable solid with metallic luster, erbium has hexagonal, close-packed crystals. Its salts are pink to red, while it forms a dark-grey powder. In lump form, the metal is stable at ordinary temperatures, and it ignites in air in its finely-divided state. It has an effective magnetic moment of 9.9 Bohr magnetons at 25 ºC (it is paramagnetic, changing to antiferromagnetic at -189 ºC and to ferromagnetic at -253 ºC). It is insoluble in water and soluble in acids. In aqueous solution, erbium is always trivalent, Er3+. It forms water-insoluble trivalent salts; evaporation of solutions generally yields hydrated salts. The metal reacts with acids, forming corresponding salts and liberating hydrogen. When heated in oxygen or air, the metal (in lump form) slowly oxidizes, forming erbium sesquioxide.
Erbium's principal uses involve its pink-colored Er3+ ions, which have optical fluorescent properties that are useful in certain laser applications. Erbium-doped glasses or crystals can be used as optical amplification media. Erbium ion emissions are also helpful in laser surgery and in certain types of laser dentistry. Erbium is also used as a photographic filter and a metallurgic additive. It can be used as a colorant for glass, cubic zirconia and porcelain. It is used in neutron-absorbing control rods, cryocoolers and (in salt form) to help stimulate metabolism in humans.
Properties of Erbium
Name | Erbium |
Symbol | Er |
Atomic number | 68 |
Atomic weight | 167.26 |
Standard state | Solid at 298 ºK |
CAS Registry ID | 7440-52-0 |
Group in periodic table | N/A |
Group name | Lanthanoid |
Period in periodic table | 6 (Lanthanoid) |
Block in periodic table | f-block |
Color | Silvery white |
Classification | Metallic |
Melting point | 1529 °C |
Boiling point | 2863 °C |
Vaporization point | 2863 ºC |
Thermal conductivity | 14.5 W/(m·K) at 298.2 °K |
Electrical resistivity | 107.0 µΩ·cm at 25 °C; 205 µΩ·cm at 1000 ºC |
Electronegativity | 1.2 |
Specific heat | 0.168 J/g mol at 20 °C |
Heat of vaporization | 285 kJ·mol-1 |
Heat of fusion | 19.9 kJ·mol-1 |
Density of liquid | 8.86 g/cm3 |
Density of solid | 9.07 g/cm3 |
Electron configuration | [Xe]4f115d16s2 |
Atomic radius | 1.758 Å (coordination number 12) |
Atomic volume | 18.49 cm3/mol |
Oxidation states | +2, +3 |