Discovery date : 1843
Discovered by: Carl Gustav Mosander
Origin of the name: Terbium was named after Ytterby, Sweden.
Allotropes :
~>TERBIUM is a chemical element with symbol Tb and atomic number 65. It is a silvery-white, rare earth metal that is malleable, ductile, and soft enough to be cut with a knife. The ninth member of the lanthanide series, terbium is a fairly electropositive metal that reacts with water, evolving hydrogen gas.
| FACT BOX | |||
| Group | Lanthanides | Melting point | 1359°C, 2478°F, 1632 K |
| Period | 6 | Boiling point | 3230°C, 5846°F, 3503 K |
| Block | f | Density (g cm−3) | 8.23 |
| Atomic number | 65 | Relative atomic mass | 158.925 |
| State at 20°C | Solid | Key isotopes | 159Tb |
| Electron configuration | [Xe] 4f96s2 | CAS number | 7440-27-9 |
| ChemSpider ID | 22397 | ChemSpider is a free chemical structure database | |
Terbium was first isolated in 1843 by the Swedish chemist Carl Mosander at Stockholm. He had already investigated cerium oxide and separated a new element from it, lanthanum, and now he focussed his attention on yttrium, discovered in 1794, because he thought this too might harbour another element. In fact Mosander was able to obtain two other metal oxides from it: terbium oxide (yellow) and erbium oxide (rose pink) and these he announced in 1843. This was not the end of the story, however, because later that century these too yielded other rare earth elements (aka lanthanoids). Today these elements are easily separated by a process known as liquid-liquid extraction.