Rhenium (Re)
transition-metalSolid
Standard Atomic Weight
186.207 uElectron configuration
[Xe] 6s2 4f14 5d5Melting point
3185.85 °CBoiling point
5595.85 °CDensity
2.08e+4 kg/m³Oxidation states
−3, −1, 0, +1, +2, +3, +4, +5, +6, +7Electronegativity (Pauling)
1.9Ionization energy (1st)
7.83352 eVDiscovery year
1925Atomic radius
135 pmDetails
Rhenium is a very dense, high-melting transition metal in group 7, chemically related to manganese and technetium but far less abundant in the crust. It is notable for retaining strength at extreme temperature and for forming stable high oxidation states, especially +7. Natural rhenium occurs mainly as a trace substitute in molybdenite rather than as separate ores, making it a by-product metal of copper-molybdenum processing.
The element is silvery white with a metallic luster; its density is exceeded only by that of platinum, iridium, and osmium, and its melting point is exceeded only by that of tungsten and carbon.
The usual commercial form of the element is powder, but it can be consolidated by pressing and resistance-sintering in a vacuum or hydrogen atmosphere. This process produces a compact shape in excess of 90 percent of the density of the metal.
Annealed rhenium is very ductile, and can be bent, coiled, or rolled. Rhenium is used as an additive to tungsten and molybdenum -based alloys to impart useful properties.
The name derives from the Latin rhenus for the Rhine river in Germany. Rhenium was discovered by x-ray spectroscopy in 1925 by German chemists Walter Noddack, Ida Tacke, and Otto Berg.
Rhenium was discovered by the German chemists Ida Tacke-Noddack, Walter Noddack and Otto Carl Berg in 1925. They detected rhenium spectroscopically in platinum ores and in the minerals columbite ((Fe, Mn, Mg)(Nb, Ta)2O6), gadolinite ((Ce, La, Nd, Y)2FeBe2Si2O10) and molybdenite (MoS2). Rhenium is present in these materials only in trace amounts. In 1928, Noddack and Berg were able to extract 1 gram of rhenium from 660 kilograms of molybdenite. Today, rhenium is obtained as a byproduct of refining molybdenum and copper.
Discovery of rhenium is generally attributed to Noddack, Tacke, and Berg, who announced in 1925 they had detected the element in platinum ore and columbite. They also found the element in gadolinite and molybdenite. By working up 660 kg of molybdenite in 1928 they were able to extract 1 g of rhenium.
Pure rhenium is a silvery-white to gray metallic solid with a bright luster when freshly prepared. It is hard, dense, and refractory, with one of the highest melting points among the elements. Powdered rhenium can be darker gray because of surface condition and particle size.
The largest use of rhenium is in nickel-based superalloys for turbine blades and other hot-section components, where small additions improve high-temperature strength and creep resistance. Rhenium is also used with platinum in reforming catalysts for petroleum refining. Tungsten-rhenium and molybdenum-rhenium alloys serve in high-temperature thermocouples, filaments, electrical contacts, and specialized X-ray tube targets. Its radioisotopes ¹⁸⁶Re and ¹⁸⁸Re have been studied and used in limited nuclear-medicine applications.
Rhenium is used in flash lamps for photography and for filaments in mass spectrographs and ion gages, but is most frequently used as an alloying agent in tungsten and molybdenum and as a catalyst for performing certain reactions to a type of hydrocarbon known as an olefin.
It is widely used as filaments for mass spectrographs and ion gauges. Rhenium-molybdenum alloys are superconductive at 10 K.
Rhenium is also used as an electrical contact material because it has good wear resistance and withstands arc corrosion. Thermocouples made of Re-W are used for measuring temperatures up to 2200C, and rhenium wire is used in photoflash lamps for photography.
Rhenium catalysts are exceptionally resistant to poisoning from nitrogen, sulfur, and phosphorus, and are used for hydrogenation of fine chemicals.
Isotopes in Geochronology
The rhenium-osmium dating method is of special interest for the dating of rhenium-bearing ores, gold deposits, copper-nickel deposits, and meteorites. This method is based on the beta-decay of 187Re (having a half-life of 41.6×109 years) to 187Os, an example of which appears in Fig. IUPAC.75.1 [515] H. M. Baioumy, L. B. Eglinton, B. Peucker-Ehrenbrink. Chem. Geol.285, 70 (2011)..
Isotopes in Medicine
186Re (with a half-life of 89 h) is a beta-emitting radioisotope that is used for cancer treatment, in particular for pain relief in bone cancer and in rheumatoid arthritis (see radiosynovectomy). It is produced from the stable isotope 185Re via the 185Re (n, γ) 186Re reaction [188] S. J. Adelstein, F. J. Manning. Isotopes for Medicine and the Life Sciences, pp. 20–25, National Academy Press, Washington DC (1995).. 186Re is also used for radiolabeling of cancer therapeutic agents [188] S. J. Adelstein, F. J. Manning. Isotopes for Medicine and the Life Sciences, pp. 20–25, National Academy Press, Washington DC (1995).. 188Re (with a half-life of 17 h) is used to irradiate coronary arteries with beta particles during insertion of an angioplasty balloon (a tiny balloon that is inserted into an artery and inflated to flatten plaque build-up and improve blood flow) and in palliative therapy, particularly for bone metastases. The beta irradiation can decrease scar tissue formation after the overstretching of arteries by angioplasty.
Rhenium chemistry spans oxidation states from negative values in carbonyl complexes to +7 in oxo compounds, with +4, +5, and +7 especially important. Perrhenic acid, HReO₄, and perrhenate salts containing ReO₄⁻ resemble perchlorates in charge and geometry but are less oxidizing under many conditions. Rhenium(VII) oxide, Re₂O₇, is the volatile anhydride of perrhenic acid. Rhenium disulfide, ReS₂, is a layered dichalcogenide with lower symmetry than many related sulfides. Dirhenium decacarbonyl, Re₂(CO)₁₀, is a common starting material in organorhenium chemistry.
See more information at the Rhenium compound page.
Massive rhenium metal is generally of low chemical reactivity, but dusts and fine powders present inhalation and fire-control concerns typical of refractory metals. Soluble perrhenate compounds can be absorbed and should be handled as toxicologically insufficiently characterized heavy-metal salts. Radioactive rhenium isotopes pose isotope-specific radiation hazards; their risk depends on half-life, emissions, chemical form, and administered or handled activity.
Rhenium is a trace element with no known essential biological role. In rocks it is commonly associated with sulfide minerals, especially molybdenite, and can be mobilized during weathering as the soluble perrhenate ion, ReO₄⁻. Seawater contains very low concentrations of dissolved rhenium, and marine sediments can record rhenium enrichment under reducing conditions. Industrial releases are mainly linked to mining, smelting, and catalyst handling.
Rhenium is obtained almost entirely as a by-product, principally from molybdenite concentrates generated in porphyry copper-molybdenum mining. During roasting, volatile rhenium oxides are captured from flue dusts and converted to ammonium perrhenate, NH₄ReO₄, or to metal powder. Supply is constrained because production depends on the output and processing choices of other metals rather than on primary rhenium mines. Demand is concentrated in aerospace superalloys and platinum-rhenium catalysts, so recycling from spent catalysts and high-value alloy scrap is important. Substitution is limited in some turbine applications, but alloy design can reduce rhenium content when supply or cost pressures are high.
Rhenium does not occur free in nature or as a compound in a distinct mineral species. It is, however, widely spread throughout the earth's crust to the extent of about 0.001 ppm. Commercial rhenium in the U.S. today is obtained from molybdenum roaster-flue dusts obtained from copper-sulfide ores mined in the vicinity of Miami, Arizona and elsewhere in Arizona and in Utah.
Some molybdenum contains from 0.002% to 0.2% rhenium. More than 150,000 troy ounces of rhenium are now being produced yearly in the United States. The total estimated Free World reserve of rhenium metal is 3500 tons. Rhenium metal is prepared by reducing ammonium perrhentate with hydrogen at elevated temperatures.
Rhenium is cosmically rare. Its stable and very long-lived isotopes are produced mainly by neutron-capture processes in earlier generations of stars, followed by dispersal into interstellar material. In planetary bodies it behaves as a siderophile and chalcophile trace element, so it partitions into metal and sulfide phases rather than forming abundant silicate minerals.
- Rhenium was one of the last stable elements to be discovered.
- Natural rhenium is dominated by ¹⁸⁷Re, which is radioactive with an extremely long half-life.
- The ¹⁸⁷Re-¹⁸⁷Os decay system is used for dating some sulfide ores and meteorites.
- Rhenium has a higher boiling point than any other element under standard tabulations.
- Perrhenate, ReO₄⁻, is often used as a nonradioactive chemical analogue for pertechnetate, TcO₄⁻.
Images
Properties
Physical
- Atomic radius (empirical)
- 135 pm Compare Atomic radius (empirical) of all elements →
- Covalent radius
- 151 pm Compare Covalent radius of all elements →
- Van der Waals radius
- 217 pm Compare Van der Waals radius of all elements →
- Metallic radius
- 128 pm Compare Metallic radius of all elements →
- Density
- 2.08 × 104 kg/m³ Compare Density of all elements →
- Molar volume
- 0.00885 L/mol
- Phase at STP
- Solid Compare Phase at STP of all elements →
- Melting point
- 3185.85 °C Compare Melting point of all elements →
- Boiling point
- 5595.85 °C Compare Boiling point of all elements →
- Thermal conductivity
- 48 W/(m·K) Compare Thermal conductivity of all elements →
- Specific heat capacity
- 0.137 J/(g·K) Compare Specific heat capacity of all elements →
- Molar heat capacity
- 25.48 J/(mol·K) Compare Molar heat capacity of all elements →
- Crystal structure
- Hexagonal close-packed Compare Crystal structure of all elements →
Chemical
- Electronegativity (Pauling)
- 1.9 Compare Electronegativity (Pauling) of all elements →
- Electronegativity (Allen)
- 1.6
- Electron affinity
- 0.15 eV
- Ionization energy (1st)
- 7.83352 eV Compare Ionization energy (1st) of all elements →
- Ionization energy (2nd)
- 16.600057 eV Compare Ionization energy (2nd) of all elements →
- Ionization energy (3rd)
- 27.000093 eV Compare Ionization energy (3rd) of all elements →
- Ionization energy (4th)
- 39.100135 eV Compare Ionization energy (4th) of all elements →
- Ionization energy (5th)
- 51.900179 eV Compare Ionization energy (5th) of all elements →
- Oxidation states
- −3, −1, 0, +1, +2, +3, +4, +5, +6, +7 Compare Oxidation states of all elements →
- Valence electrons
- 7 Compare Valence electrons of all elements →
- Electron configuration
- [Xe] 6s2 4f14 5d5
Thermodynamic
- Heat of fusion
- 0.34927709 eV Compare Heat of fusion of all elements →
- Heat of vaporization
- 7.358657 eV Compare Heat of vaporization of all elements →
- Heat of sublimation
- 8.032337 eV
- Heat of atomization
- 8.032337 eV
- Atomization enthalpy
- 8.021972 eV
Nuclear
- Protons
- 75 Compare Protons of all elements →
- Neutrons
- 110 Compare Neutrons of all elements →
- Known isotopes
- 41 Compare Known isotopes of all elements →
- Stable isotopes
- 1 Compare Stable isotopes of all elements →
- Most stable isotope
- Re-185
- Discovery year
- 1925
Abundance
- Abundance (Earth's crust)
- 7e-4 mg/kg Compare Abundance (Earth's crust) of all elements →
- Abundance (ocean)
- 4 × 10−6 mg/L Compare Abundance (ocean) of all elements →
Crystal Structure
- Lattice constant a
- 276 pm
Electronic Structure
- Electrons per shell
- 2, 8, 18, 32, 13, 2 Compare Electrons per shell of all elements →
Identifiers
- CAS number
- 7440-15-5 Compare CAS number of all elements →
- Term symbol
- 6S5/2
- InChI
- InChI=1S/Re
- InChI Key
- WUAPFZMCVAUBPE-UHFFFAOYSA-N
Electron Configuration Measured
Re: 4f¹⁴ 5d⁵ 6s²[Xe] 4f¹⁴ 5d⁵ 6s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d⁵ 6s²Atomic model
Isotopes change neutron count, mass, and stability — not the electron configuration of a neutral atom.
Schematic atomic model, not to scale.
Atomic Fingerprint
Emission / Absorption Spectrum
Isotope Distribution
| Mass number | Atomic mass (u) | Natural abundance | Half-life |
|---|---|---|---|
| 185 Stable | 184.9529545 ± 0.0000013 | 37.4000% | Stable |
Phase / State
Reason: 3160.8 °C below melting point (3185.85 °C)
Schematic, not to scale
Phase transition points
Transition energies
Energy required to melt 1 mol at melting point
Energy required to vaporize 1 mol at boiling point
Energy required to sublime 1 mol at sublimation point
Density
At standard conditions
At standard conditions
Atomic Spectra
Showing 10 of 75. Sorted by ion charge (ascending).
Lines Holdings ?
| Ion | Charge | Total lines | Transition probabilities | Level designations |
|---|---|---|---|---|
| Re I | 0 | 432 | 0 | 0 |
| Re II | +1 | 56 | 0 | 0 |
| Re III | +2 | 1381 | 1381 | 1381 |
| Re IV | +3 | 982 | 982 | 982 |
| Re V | +4 | 401 | 401 | 401 |
Levels Holdings ?
| Ion | Charge | Levels |
|---|---|---|
| Re I | 0 | 291 |
| Re II | +1 | 140 |
| Re III | +2 | 232 |
| Re IV | +3 | 162 |
| Re V | +4 | 80 |
| Re VI | +5 | 2 |
| Re VII | +6 | 2 |
| Re VIII | +7 | 2 |
| Re IX | +8 | 2 |
| Re X | +9 | 2 |
Ionic Radii
| Charge | Coordination | Spin | Radius |
|---|---|---|---|
| +4 | 6 | N/A | 63 pm |
| +5 | 6 | N/A | 57.99999999999999 pm |
| +6 | 6 | N/A | 55.00000000000001 pm |
| +7 | 4 | N/A | 38 pm |
| +7 | 6 | N/A | 53 pm |
Compounds
Isotopes (1)
Natural rhenium is a mixture of two stable isotopes. Twenty six other unstable isotopes are recognized.
| Mass number | Atomic mass (u) | Natural abundance | Half-life | Decay mode | |
|---|---|---|---|---|---|
| 185 Stable | 184.9529545 ± 0.0000013 | 37.4000% ± 0.0200% | Stable | stable |
Extended Properties
Covalent Radii (Extended)
- Covalent radius (Pyykkö)
- 131 pm
- Covalent radius (Pyykkö, double)
- 119 pm
- Covalent radius (Pyykkö, triple)
- 110 pm
Van der Waals Radii
- Batsanov
- 205 pm
- Alvarez
- 249 pm
- UFF
- 295.4 pm
- MM3
- 237 pm
Atomic & Metallic Radii
- Atomic radius (Rahm)
- 249 pm
- Metallic radius (C12)
- 137 pm
Numbering Scales
- Mendeleev
- 57
- Pettifor
- 59
- Glawe
- 58
Electronegativity Scales
- Ghosh
- 0
- Miedema
- 5
- Gunnarsson–Lundqvist
- 5
- Robles–Bartolotti
- 4
Polarizability & Dispersion
- Dipole polarizability
- 62 a.u.
- Dipole polarizability (unc.)
- 3 a.u.
- C₆ (Gould–Bučko)
- 663 Ha·Bohr6
Miedema Parameters
- Miedema molar volume
- 8.85 cm3/mol
- Miedema electron density
- 6
Supply Risk & Economics
- Production concentration
- 51
- Relative supply risk
- 6
- Reserve distribution
- 52
- Political stability (top producer)
- 68
- Political stability (top reserve)
- 68
Phase Transitions & Allotropes
| Melting point | 3458.15 K |
| Boiling point | 5863.15 K |
Oxidation State Categories
Advanced Reference Data
Screening Constants (14)
| n | Orbital | σ |
|---|---|---|
| 1 | s | 1.4522 |
| 2 | p | 4.438 |
| 2 | s | 19.5902 |
| 3 | d | 13.5453 |
| 3 | p | 21.5655 |
| 3 | s | 22.3515 |
| 4 | d | 36.9456 |
| 4 | f | 39.0752 |
| 4 | p | 34.6268 |
| 4 | s | 33.6436 |
Crystal Radii Detail (5)
| Charge | CN | Spin | rcrystal (pm) | Origin |
|---|---|---|---|---|
| 4 | VI | 77 | from r^3 vs V plots, from metallic oxides, | |
| 5 | VI | 72 | estimated, | |
| 6 | VI | 69 | estimated, | |
| 7 | IV | 52 | ||
| 7 | VI | 67 |
Isotope Decay Modes (54)
| Isotope | Mode | Intensity |
|---|---|---|
| 159 | p | — |
| 159 | A | — |
| 160 | p | 89% |
| 160 | A | 11% |
| 161 | p | 100% |
| 161 | A | — |
| 162 | A | 94% |
| 162 | B+ | — |
| 163 | B+ | — |
| 163 | A | 32% |
X‑ray Scattering Factors (516)
| Energy (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 1.8209 |
| 10.1617 | — | 1.91145 |
| 10.3261 | — | 2.0065 |
| 10.4931 | — | 2.10629 |
| 10.6628 | — | 2.21103 |
| 10.8353 | — | 2.28753 |
| 11.0106 | — | 2.3602 |
| 11.1886 | — | 2.43518 |
| 11.3696 | — | 2.51255 |
| 11.5535 | — | 2.59237 |
Additional Data
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
7×10-4 milligrams per kilogram
References (1)
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
4×10-6 milligrams per liter
References (1)
Sources
Sources of this element.
Rhenium does not occur free in nature or as a compound in a distinct mineral species. It is, however, widely spread throughout the earth's crust to the extent of about 0.001 ppm. Commercial rhenium in the U.S. today is obtained from molybdenum roaster-flue dusts obtained from copper-sulfide ores mined in the vicinity of Miami, Arizona and elsewhere in Arizona and in Utah.
Some molybdenum contains from 0.002% to 0.2% rhenium. More than 150,000 troy ounces of rhenium are now being produced yearly in the United States. The total estimated Free World reserve of rhenium metal is 3500 tons. Rhenium metal is prepared by reducing ammonium perrhentate with hydrogen at elevated temperatures.
References (1)
- [6] Rhenium https://periodic.lanl.gov/75.shtml
References
(9)
Data deposited in or computed by PubChem
The half-life and atomic mass data was provided by the Atomic Mass Data Center at the International Atomic Energy Agency.
Element data are cited from the Atomic weights of the elements (an IUPAC Technical Report). The IUPAC periodic table of elements can be found at https://iupac.org/what-we-do/periodic-table-of-elements/. Additional information can be found within IUPAC publication doi:10.1515/pac-2015-0703 Copyright © 2020 International Union of Pure and Applied Chemistry.
The information are cited from Pure Appl. Chem. 2018; 90(12): 1833-2092, https://doi.org/10.1515/pac-2015-0703.
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This section provides all form of data related to element Rhenium.
The element property data was retrieved from publications.