Rhenium
Definition and meaning of Rhenium in chemistry.
![Rhenium element card: symbol Re, atomic number 75, atomic mass 186.21, electron configuration [Xe] 4f¹⁴ 5d⁵ 6s², oxidation states +4, Transition metal, group 7, period 6, solid at room temperature.](/assets/images/terms/rhenium-chemical-element.webp)
Rhenium is a dense, silvery-white transition metal with the chemical symbol Re and atomic number 75. It is one of the rarest elements in the Earth's crust. This heavy metal can tolerate extreme heat, making it vital for building jet engines.
In more detail
Rhenium has one of the highest melting and boiling points of all stable chemical elements. Only tungsten and carbon can absorb more heat before they melt or turn into gas. You will never find pure rhenium sitting alone in the ground.
It does not even form its own unique mineral deposits in nature. Mining companies extract it in tiny amounts while refining copper and molybdenum ores. The solid metal resists physical wear and steady stress extremely well.
It fights off high-temperature oxidation, which is another term for rusting, better than other metals. Chemists place rhenium in group 7 on the periodic table. The element can take on many different oxidation states, ranging from -1 to +7.
The +7 oxidation state is the most stable and common in lab compounds. This allows it to form compounds like rhenium heptoxide, which is Re2O7. It is also used as a catalyst in reactions that make high-octane gasoline.
A common student misconception is that rhenium is weak because it is so rare. In reality, adding just a tiny bit of rhenium makes other metals much stronger. It dramatically improves their creep resistance, which stops metals from warping under high heat. This single feature drives almost all global demand for the metal.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Re |
| Atomic number | 75 |
| Atomic mass | 186.21 u |
| Category | Transition-Metal |
| Boiling point | 5596 °C |
Engineers use rhenium to build turbine blades for modern jet engines. They mix rhenium with nickel to create a strong alloy that resists warping. This allows the engine to run safely at much hotter temperatures to save fuel.
Frequently asked questions
Is rhenium a noble metal?
It resists rusting like noble metals such as gold or platinum. However, chemists officially group it as a refractory transition metal due to its high melting point.
Why does rhenium cost so much?
It is extremely rare in the Earth's crust and hard to extract. Factories must use a long, difficult process to separate it from other metal ores.
What is creep resistance in alloys?
It is the ability of a metal to resist warping or changing shape under constant stress. Rhenium adds this vital strength to engine alloys at high temperatures.
Related terms
Sources & references
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