| Tecken | Er |
| Atomnummer | 68 |
| Grupp | - |
| Period | 6 |
| Block | f |
| Ämnesklass | Lantanoid |
| Utseende | Silvery white |
| Färg | Silver |
| Antal protoner | 68 p+ |
| Antal neutroner | 99 n0 |
| Antal elektroner | 68 e- |
| Fas vid STP | Fast |
| Densitet | 9.066 g/cm3 |
| Relativ atommassa | 167.259 u |
| Smältpunkt | 1802 K 1528.85 °C 2783.93 °F |
| Kokpunkt | 3141 K 2867.85 °C 5194.13 °F |
| Ångbildningsvärme | 292.88 kJ/mol |
| Elektronegativitet (Paulingskalan) | 1.24 |
| Elektronaffinitet | 30.1 kJ/mol |
| Oxidationstal | 0, +1, +2, +3 (a basic oxide) |
| Jonisationspotential |
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| Upptäckt | Carl Gustaf Mosander (1843) |
Upptäckten av erbium Erbium (for Ytterby, a village in Sweden) was discovered by Carl Gustaf Mosander in 1843. Mosander was working with a sample of what was thought to be the single metal oxide yttria, derived from the mineral gadolinite. He discovered that the sample contained at least two metal oxides in addition to pure yttria, which he named "erbia" and "terbia" after the village of Ytterby where the gadolinite had been found. Mosander was not certain of the purity of the oxides and later tests confirmed his uncertainty. Not only did the "yttria" contain yttrium, erbium, and terbium; in the ensuing years, chemists, geologists and spectroscopists discovered five additional elements: ytterbium, scandium, thulium, holmium, and gadolinium. | |