![Diagram of the [Re2Cl8]2- ion showing two rhenium atoms connected by four parallel lines representing a quadruple bond, with each rhenium atom surrounded by four chloride ions.](https://cdn.britannica.com/28/7528-050-57A3E696/link-character.jpg)
- Key People:
- Ida Noddack
- Related Topics:
- chemical element
- transition metal
- technetium
- rhenium-187
rhenium
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What is rhenium?
Rhenium (Re) is a rare, silvery-white metal in Group 7 of the periodic table with a high density. The German chemists Ida and Walter Noddack and Otto Carl Berg discovered it in 1925.
Rhenium does not occur as a free element or distinct mineral but is widely distributed in small amounts in other minerals. Chile leads in rhenium recovery, followed by the United States, Poland, Uzbekistan, and Kazakhstan.
The metal is extracted from flue dust and gases and converted to ammonium perrhenate, then reduced to metal with hydrogen. Rhenium is extremely hard, resists wear and corrosion, and has one of the highest melting points of all elements.
Ida Noddack also first proposed nuclear fission.
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Where is rhenium found on the periodic table?
Rhenium (Re) is a chemical element and a very rare metal that sits in Group 7 (VIIb) of the periodic table. Russian chemist Dmitry Ivanovich Mendeleyev predicted the element's existence in 1869, but it wasn't discovered until 1925 by German chemists Ida and Walter Noddack and Otto Carl Berg.
Rhenium has an atomic number of 75 and an atomic weight of 186.2. This silvery-white metal is exceptionally hard and boasts one of the highest melting points among the elements, surpassed only by tungsten and carbon.
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What are some physical properties of rhenium?
Rhenium (Re), a chemical element, is a very rare metal in Group 7 of the periodic table and also one of the densest elements.
Some physical properties of Rhenium:
* Silvery white color
* Extremely hard
* Resists wear and corrosion well
* Melting point of 3,180 °C (5,756 °F)
* Boiling point of 5,627 °C (10,161 °F)
* Specific gravity of 20.5 at 20 °C (68 °F)
* The metal powder slowly oxidizes in air above 150 °C (300 °F) and rapidly at higher temperatures to form the yellow heptoxide, Re2O7.
* Not soluble in hydrochloric acid and dissolves only slowly in other acids.1 Britannica SourceCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
How is rhenium obtained or produced?
Rhenium (Re) is a chemical element that does not occur free in nature or as a compound in any distinct mineral. Instead, it is widely distributed in small amounts in other minerals, usually in concentrations averaging about 0.001 parts per million.
The recovery of rhenium is aided by the concentration of its volatile heptoxide (Re₂O₇) in the flue dust and gases given off during the smelting of molybdenite ore, or from its concentration with the platinum metals in the anode sludge during electrolytic copper refining. The black metal powder is extracted from the gases and dust by leaching or scrubbing them with water to dissolve the oxide, Re₂O₇, which in turn can be converted to ammonium perrhenate, NH₄ReO₄, and then reduced to the metal with hydrogen. The powder may be compressed and sintered into bars in hydrogen at elevated temperatures. Cold-working and annealing permit the fabrication of wire or foil. Chile is the world leader in rhenium recovery, followed by the United States, Poland, Uzbekistan, and Kazakhstan.
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What are the main uses of rhenium?
Rhenium (Re) is a rare, dense metal in Group 7 of the periodic table. It was discovered in 1925 and is known for its high melting point and resistance to wear and corrosion.
Uses of rhenium:
* Turbine blades in fighter-jet engines
* Fountain pen points
* High-temperature thermocouples (with platinum)
* Catalysts
* Electrical contact points
* Instrument-bearing points
* Electrical components, such as flashbulb filaments as an alloy with tungsten2 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
Why is rhenium considered a valuable or rare element?
Rhenium is considered valuable and rare due to several factors:
- Rarity in nature Rhenium does not occur as a free element or as a compound in any distinct mineral. It is widely distributed in small amounts in other minerals, usually in concentrations averaging about 0.001 parts per million.
- Limited application The metal and its alloys have found limited application as turbine blades in fighter-jet engines, fountain pen points, high-temperature thermocouples (with platinum), catalysts, electrical contact points, and instrument-bearing points and in electrical components, such as in flashbulb filaments as an alloy with tungsten.
- Difficult extraction The recovery of rhenium is aided by the concentration of its volatile heptoxide (Re2O7) in the flue dust and gases given off during the smelting of molybdenite ore or from its concentration with the platinum metals in the anode sludge during electrolytic copper refining.
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rhenium (Re), chemical element, a very rare metal of Group 7 (VIIb) of the periodic table and one of the densest elements. Predicted by the Russian chemist Dmitry Ivanovich Mendeleyev (1869) as chemically related to manganese, rhenium was discovered (1925) by the German chemists Ida and Walter Noddack and Otto Carl Berg. The metal and its alloys have found limited application as turbine blades in fighter-jet engines, fountain pen points, high-temperature thermocouples (with platinum), catalysts, electrical contact points, and instrument-bearing points and in electrical components, such as in flashbulb filaments as an alloy with tungsten.
Rhenium does not occur free in nature or as a compound in any distinct mineral; instead it is widely distributed in small amounts in other minerals, usually in concentrations averaging about 0.001 parts per million. Chile is the world leader in rhenium recovery, followed by the United States, Poland, Uzbekistan, and Kazakhstan.
Rhenium occurs up to about 20 parts per million in molybdenite and to a lesser extent in sulfidic copper ores. The recovery of rhenium is aided by the concentration of its volatile heptoxide (Re2O7) in the flue dust and gases given off during the smelting of molybdenite ore or from its concentration with the platinum metals in the anode sludge during electrolytic copper refining. The black metal powder is extracted from the gases and dust by leaching or scrubbing them with water to dissolve the oxide, Re2O7, which in turn can be converted to ammonium perrhenate, NH4ReO4, and then reduced to the metal with hydrogen. The powder may be compressed and sintered into bars in hydrogen at elevated temperatures. Cold-working and annealing permit the fabrication of wire or foil.
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Rhenium metal is silvery white and extremely hard; it resists wear and corrosion very well and has one of the highest melting points of the elements. (The melting point of rhenium, 3,180 °C [5,756 °F], is exceeded only by those of tungsten and carbon.) The metal powder slowly oxidizes in air above 150 °C (300 °F) and rapidly at higher temperatures to form the yellow heptoxide, Re2O7. The metal is not soluble in hydrochloric acid and dissolves only slowly in other acids. There is evidence for the existence of rhenium in each of the oxidation states from −1 to +7; the most common states are +3, +4, +5, and especially +7. Rhenium’s most characteristic and important compounds are formed in the oxidation states +4 and +7, although compounds are known in all formal oxidation states from −1 to +7. Perrhenic acid (HReO4) and its anhydride, the heptoxide, and the perrhenates are common stable compounds in which rhenium is in the +7 state. Natural rhenium is a mixture of the stable isotope rhenium-185 (37.4 percent) and the radioactive rhenium-187 (62.6 percent, 4.1 × 1010-year half-life).
| atomic number | 75 |
|---|---|
| atomic weight | 186.2 |
| melting point | 3,180 °C (5,756 °F) |
| boiling point | 5,627 °C (10,161 °F) |
| specific gravity | 20.5 at 20 °C (68 °F) |
| oxidation states | +1, +2, +3, +4, +5, +6, +7 |
| electron configuration | [Xe]4f 145d56s2 |