Discovery date : 1925
Discovered by: Walter Noddack, Ida Tacke and Otto Berg
Origin of the name: The name is derived from the Latin name for the Rhine, 'Rhenus'.
Allotropes :
~>RHENIUM is a chemical element with symbol Re and atomic number 75. It is a silvery-white, heavy, third-row transition metal in group 7 of the periodic table. With an estimated average concentration of 1 part per billion (ppb), rhenium is one of the rarest elements in the crust. Rhenium has the third-highest melting point.
| FACT BOX | |||
| Group | 7 | Melting point | 3185°C, 5765°F, 3458 K |
| Period | 6 | Boiling point | 5590°C, 10094°F, 5863 K |
| Block | d | Density (g cm−3) | 20.8 |
| Atomic number | 75 | Relative atomic mass | 186.207 |
| State at 20°C | Solid | Key isotopes | 187Re |
| Electron configuration | [Xe] 4f145d56s2 | CAS number | 7440-15-5 |
| ChemSpider ID | 22388 | ChemSpider is a free chemical structure database | |
The periodic table had two vacant slots below manganese and finding these missing elements, technetium and rhenium, proved difficult. Rhenium was the lower one and indeed it was the last stable, non-radioactive, naturally-occurring element to be discovered. In 1905, Masataka Ogawa found it in the mineral thorianite from Sri Lanka. He realised from lines in its atomic spectrum that it contained an unknown element. He wrongly thought it was the one directly below manganese and so his claim was discounted at the time. However, a re-examination of Ogawa’s original photographic spectra proved he had discovered rhenium.
The isolation of rhenium was finally achieved in May 1925 by Walter Noddack and Ida Tacke working in Berlin. They concentrated it from the ore gadolinite in which it was an impurity.