Rhenium (Re)
Transition metal
Rhenium was the last stable element ever discovered (1925), and it remains one of the rarest. Jet engines depend on it: superalloy turbine blades with a few percent rhenium survive white-hot combustion for thousands of hours.
Position on the periodic table
Atomic properties
| Atomic number | 75 |
|---|---|
| Atomic mass | 186.207 amu |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d5 |
| Noble gas shorthand | [Xe] 4f14 5d5 6s2 |
| Electrons per shell | 2, 8, 18, 32, 13, 2 |
| Valence electrons (outer shell) | 2 |
| Common oxidation states | +7, +4 |
| Electronegativity (Pauling) | 1.9 |
| Covalent radius (approx.) | 151 pm |
| First ionization energy | 760 kJ/mol |
| Electron affinity | 5.8 kJ/mol |
Physical properties
| State at 25 °C | Solid |
|---|---|
| Density | 21.02 g/cm³ |
| Melting point | 3185.8 °C (3459 K) |
| Boiling point | 5595.9 °C (5869 K) |
| Appearance | silvery-grayish |
| Radioactive | No |
| Origin | Occurs naturally |
Electron configuration of rhenium
Rhenium's ground-state electron configuration is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d5, usually shortened to [Xe] 4f14 5d5 6s2. Its electrons occupy 6 shells (2, 8, 18, 32, 13, 2), placing it in period 6 of the d-block. Explore it interactively in the electron configuration calculator.
Uses of rhenium
- Single-crystal turbine blades for jet engines
- Platinum-rhenium catalysts for high-octane petrol
- Thermocouples for extreme temperatures
- Filaments in mass spectrometers
Biological role: None known.
Occurrence: About 1 part per billion of the crust; recovered from molybdenum roasting flue dust.
Common compounds of rhenium
Re2O7
Rhenium(VII) oxide
History and discovery
Discovered: 1925 — Masataka Ogawa. Name origin: From Rhenus, the Latin name of the river Rhine.
Walter Noddack, Ida Tacke and Otto Berg identified rhenium in 1925 — filling one of the last gaps in the periodic table.
Safety notes
Low toxicity in normal handling.
Educational context only — always follow your school's laboratory rules and never handle chemicals without proper supervision. See our disclaimer.
Practice questions
Quick practice: Rhenium
1. What is the chemical symbol of Rhenium?
2. What is the atomic number of Rhenium?
3. Which category does Rhenium belong to?
4. What is the state of Rhenium at room temperature?
5. Which period of the periodic table is Rhenium in?
Rhenium FAQs
What is the atomic number of rhenium?
Rhenium's atomic number is 75 — every rhenium atom has 75 protons in its nucleus.
What is the symbol for rhenium?
Re. From Rhenus, the Latin name of the river Rhine.
Is rhenium a metal, nonmetal, or metalloid?
Rhenium is classified as a transition metal.
What state is rhenium at room temperature?
At about 25 °C, rhenium is a solid. It melts at 3185.8 °C.
What is rhenium used for?
Key uses include: single-crystal turbine blades for jet engines; platinum-rhenium catalysts for high-octane petrol; thermocouples for extreme temperatures.
Related elements
Keep working with this element
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