Rhenium
Definition and meaning of Rhenium in chemistry.
Rhenium is a chemical element with the symbol Re and atomic number 75. It is a dense, silvery-white transition metal that ranks solidly among the absolute rarest elements found in the Earth's continental crust.
In more detail
Rhenium possesses one of the highest melting points and boiling points of all known stable elements, being surpassed only by tungsten and carbon in terms of sheer melting temperature. It does not occur freely in nature or even in a specific rhenium-bearing mineral, but is instead painstakingly extracted as a trace byproduct during the commercial refinement of molybdenum and copper ores. The solid metal is incredibly highly resistant to physical wear and withstands high-temperature atmospheric corrosion significantly better than many other heavy refractory metals. Found firmly in group 7 of the periodic table, rhenium exhibits a massively broad spectrum of potential oxidation states ranging from -1 to +7, forming incredibly varied compounds such as rhenium heptoxide (Re2O7). Its unique ability to dramatically improve the high-temperature creep resistance of nickel-based superalloys strongly drives its primary global industrial demand.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Re |
| Atomic number | 75 |
| Atomic mass | 186.21 u |
| Category | Transition Metal |
| State at room temperature | Solid |
| Boiling point | 5596 °C |
| Discovered by | Walter Noddack, Ida Tacke, and Otto Berg |
| Discovery year | 1925 |
Rhenium is heavily utilized in single-crystal superalloys for manufacturing high-stress turbine blades in modern jet engines, allowing the aircraft to operate safely at extreme, highly efficient temperatures.
Frequently asked questions
Is rhenium properly classified as a noble metal in chemistry?
While it certainly shares some inert, corrosion-resistant characteristics with the traditional noble metals, it is generally and officially classified as a heavy refractory transition metal.
Why is rhenium continually priced so highly on the commodities market?
Its exceedingly high price is entirely due to its extreme physical scarcity in the Earth's crust and the highly complex, multi-stage extraction process required to isolate it from molybdenum concentrates.