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About Rhenium

Rhenium Bohr

By the early twentieth century, what we know as the modern periodic table had largely taken shape. For the most part, what chemical discoveries remained would require the use of nuclear reactors rather than the traditional chemist’s patient examination and chemical analysis of unusual ores. There were, however, a few remaining holes in the table outside of the bottom rows that would later come to be filled with lab-produced radioactive elements; two of these missing elements were numbers 43 and 75.

Both of these elements had been predicted by Mendeleev, who had named them ekamanganese and dwimanganese respectively, but despite many attempts and declarations of discovery later deemed false, both elements remained elusive until 1924. In that year, the team of Walter Noddack and Ida Tacke, two German chemists who later married, with the assistance of Otto Berg, believed that they had found both of these missing elements in platinum ores, an assertion they based on spectral data. They named element 43 “masurian” for Noddack’s birthplace in the masurian marshes district, and element 75 “rhenium” from Tacke’s birthplace in Rhenany-Rhineland. Unfortunately, the team was only able to actually isolate substantial quantities of rhenium, and later theories convinced the scientific community that in fact, element 43 would be too unstable to be found by natural means. This lead to widespread disrespect for Tacke and Noddack as scientists, despite their verified discovery of one of the missing elements.

The early extraction and purification process for the rare element rhenium was complicated and expensive, which long delayed its industrial use. Even today, its applications are limited by its low availability, and is used primarily in functions where small quantities can provide substantial benefits. One of these functions is as an alloy additive: rhenium is a component of many heat-resistant superalloys. Nickel-based superalloys are frequently used in jet engines, where they are valued for high resistance to creep. Tungsten-rhenium and molybdenum-rhenium are used in thermocouples most often deployed for sensing extremely high temperatures. Rhenium-containing alloys may also find use in crucibles, self-cleaning electrical contacts, electromagnets, ionization gauges, and mass spectrographs. The other major use of rhenium is as a catalyst; it serves this function in the processing of petroleum, alongside platinum in catalytic converters, and in a number of niche or still developing applications. Additionally, Re-188 and Re-186 are used in cancer radiotherapy.

Rhenium is most often found in small quantities in molybdenum deposits, and is obtained through processing of molybdenum concentrates. Additionally, platinum-rhenium catalysts and rhenium alloy scrap are frequently recycled.

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High-temperature rhenium super-alloys are used to make jet engine parts. Platinum-rhenium catalysts are used in lead-free, high-octane, gasoline. Rhenium is also used as a filament for mass spectrographs and ion gauges. Because rhenium has good wear resistance and withstands arc corrosion, it is used as an electrical High Purity (99.999%) Rhenium (Re) Sputtering Targetcontact material. Thermocouples made of Re-W are used for measuring temperatures up to 2200C, and rhenium wire is used in photographic flash lamps. Rhenium is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity). High Purity (99.999%) Rhenium Oxide (ReO2) PowderElemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes. Rhenium nanoparticles and nanopowders provide ultra-high surface area. Rhenium oxides are available in powder and dense pellet form for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Rhenium fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Rhenium is also available in soluble forms including as its chlorides. These compounds can be manufactured as solutions at specified stoichiometries.

Rhenium Properties

Rhenium(Re) atomic and molecular weight, atomic number and elemental symbolRhenium is a Block D, Group 7, Period 6 element. The number of electrons in each of rhenium's shells is 2, 8, 18, 32, 13, 2 and its electron configuration is [Xe] 4f14 5d5 6s2. Rhenium Bohr ModelThe rhenium atom has a radius of and its Van der Waals radius is In its elemental form, CAS 7440-15-5, rhenium has a silvery-white appearance. Rhenium is the fourth densest element exceeded only by platinum, iridium, and osmium. Elemental RheniumRhenium's high melting point is exceeded only by tungsten and carbon. Rhenium is found in small amounts in gadolinite and molybdenite. It is usually extracted from the flue dusts of molybdenum smelters. Annual world production is around 4.5 tons. Rhenium was first isolated by Walter Noddack and Ida Tacke in 1908. The name rhenium originates from the Latin word 'Rhenus' meaning "Rhine" after the area where Tacke was born.

Symbol: Re
Atomic Number: 75
Atomic Weight: 186.207
Element Category: transition metal
Group, Period, Block: 7, 6, d
Color: grayish white/ silvery-white
Other Names: Rhénium, Renio, Rênio
Melting Point: 3186 °C, 5767 °F, 3459 K
Boiling Point: 5596 °C, 10105 °F, 5869 K
Density: 21.02 g·cm3
Liquid Density @ Melting Point: 18.9 g·cm3
Density @ 20°C: 21.0 g/cm3
Density of Solid: 21020 kg·m3
Specific Heat: 0.14 (kJ/kg K)
Superconductivity Temperature: 1.70 [or -271.4 °C (-456.5 °F)] K
Triple Point: N/A
Critical Point: N/A
Heat of Fusion (kJ·mol-1): 33.1
Heat of Vaporization (kJ·mol-1): 704.25
Heat of Atomization (kJ·mol-1): 769
Thermal Conductivity: 48.0 W·m-1·K-1
Thermal Expansion: 6.2 µm/(m·K)
Electrical Resistivity: (20 °C) 193 nΩ·m
Tensile Strength: N/A
Molar Heat Capacity: 25.48 J·mol-1·K-1
Young's Modulus: 463 GPa
Shear Modulus: 178 GPa
Bulk Modulus: 370 GPa
Poisson Ratio: 0.3
Mohs Hardness: 7
Vickers Hardness: 2450 MPa
Brinell Hardness: 1320 MPa
Speed of Sound: (20 °C) 4700 m·s-1
Pauling Electronegativity: 1.9
Sanderson Electronegativity: N/A
Allred Rochow Electronegativity: 1.46
Mulliken-Jaffe Electronegativity: N/A
Allen Electronegativity: N/A
Pauling Electropositivity: 2.1
Reflectivity (%): N/A
Refractive Index: N/A
Electrons: 75
Protons: 75
Neutrons: 111
Electron Configuration: [Xe] 4f14 5d5 6s2
Atomic Radius: 137 pm
Atomic Radius,
non-bonded (Å):
Covalent Radius: 151±7 pm
Covalent Radius (Å): 1.41
Van der Waals Radius: 200 pm
Oxidation States: 7, 6, 5, 4, 3, 2, 1, 0, -1 (mildly acidic oxide)
Phase: Solid
Crystal Structure: hexagonal close-packed
Magnetic Ordering: paramagnetic
Electron Affinity (kJ·mol-1) 14.468
1st Ionization Energy: 760 kJ·mol-1
2nd Ionization Energy: 1260 kJ·mol-1
3rd Ionization Energy: 2510 kJ·mol-1
CAS Number: 7440-15-5
EC Number: 231-124-5
MDL Number: MFCD00011195
Beilstein Number: N/A
SMILES Identifier: [Re]
InChI Identifier: InChI=1S/Re
PubChem CID: 23947
ChemSpider ID: 22388
Earth - Total: 60 ppb
Mercury - Total: 46 ppb
Venus - Total: 64 ppb
Earth - Seawater (Oceans), ppb by weight: 0.001
Earth - Seawater (Oceans), ppb by atoms: 0.000033
Earth -  Crust (Crustal Rocks), ppb by weight: 2.6
Earth -  Crust (Crustal Rocks), ppb by atoms: 0.3
Sun - Total, ppb by weight: 0.1
Sun - Total, ppb by atoms: 0.0005
Stream, ppb by weight: N/A
Stream, ppb by atoms: N/A
Meterorite (Carbonaceous), ppb by weight: 50
Meterorite (Carbonaceous), ppb by atoms: 5
Typical Human Body, ppb by weight: N/A
Typical Human Body, ppb by atom: N/A
Universe, ppb by weight: 0.2
Universe, ppb by atom: 0.001
Discovered By: Masataka Ogawa
Discovery Date: 1908
First Isolation: Masataka Ogawa (1908)

Health, Safety & Transportation Information for Rhenium

Very little is known about the toxicity of rhenium and its compounds. Safety data for Rhenium and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab. The below information applies to elemental (metallic) Rhenium.

Safety Data
Material Safety Data Sheet MSDS
Signal Word Danger
Hazard Statements H228
Hazard Codes F
Risk Codes 11
Safety Precautions 16
RTECS Number VI0780000
Transport Information N/A
WGK Germany nwg
Globally Harmonized System of
Classification and Labelling (GHS)

Rhenium Isotopes

Naturally occurring rhenium (Re) has two isotopes: 185Re (37.4%) and 187Re (62.6%) .

Nuclide Isotopic Mass Half-Life Mode of Decay Nuclear Spin Magnetic Moment Binding Energy (MeV) Natural Abundance
(% by atom)
160Re 159.98212(43)# 860(120) µs [0.82(+15-9) ms] p to 159W; a to 156Ta (2-) N/A 1227.07 -
161Re 160.97759(22) 0.37(4) ms p to 160W 1/2+ N/A 1244.47 -
162Re 161.97600(22)# 107(13) ms a to 158Ta; ß+ to 162W (2-) N/A 1252.54 -
163Re 162.972081(21) 390(70) ms ß+ to 163W; a to 159Ta (1/2+) N/A 1260.62 -
164Re 163.97032(17)# 0.53(23) s a to 160Ta; ß+ to 164W high N/A 1268.7 -
165Re 164.967089(30) 1# s ß+ to 165W; a to 161Ta 1/2+# N/A 1286.1 -
166Re 165.96581(9)# 2# s ß+ to 166W; a to 162Ta 2-# N/A 1294.18 -
167Re 166.96260(6)# 3.4(4) s a to 163Ta; ß+ to 167W 9/2-# N/A 1302.25 -
168Re 167.96157(3) 4.4(1) s ß+ to 168W; a to 164Ta (5+,6+,7+) N/A 1310.33 -
169Re 168.95879(3) 8.1(5) s ß+ to 169W; a to 165Ta 9/2-# N/A 1327.73 -
170Re 169.958220(28) 9.2(2) s ß+ to 170W; a to 166Ta (5+) N/A 1335.81 -
171Re 170.95572(3) 15.2(4) s ß+ to 171W (9/2-) N/A 1343.89 -
172Re 171.95542(6) 15(3) s ß+ to 172W -5 N/A 1351.96 -
173Re 172.95324(3) 1.98(26) min ß+ to 173W (5/2-) N/A 1360.04 -
174Re 173.95312(3) 2.40(4) min ß+ to 174W N/A N/A 1368.12 -
175Re 174.95138(3) 5.89(5) min ß+ to 175W (5/2-) N/A 1376.2 -
176Re 175.95162(3) 5.3(3) min ß+ to 176W 3+ N/A 1384.28 -
177Re 176.95033(3) 14(1) min ß+ to 177W 5/2- N/A 1392.36 -
178Re 177.95099(3) 13.2(2) min ß+ to 178W (3+) N/A 1400.44 -
179Re 178.949988(26) 19.5(1) min ß+ to 179W (5/2)+ N/A 1417.83 -
180Re 179.950789(23) 2.44(6) min ß+ to 180W (1)- N/A 1416.59 -
181Re 180.950068(14) 19.9(7) h ß+ to 181W 5/2+ N/A 1424.67 -
182Re 181.95121(11) 64.0(5) h EC to 182W 7+ 2.8 1432.75 -
183Re 182.950820(9) 70.0(14) d EC to 183W 5/2+ 3.17 1440.83 -
184Re 183.952521(5) 38.0(5) d EC to 184W 3(-) 2.53 1448.91 -
185Re 184.9529550(13) Observationally Stable - 5/2+ 3.1871 1456.99 37.4
186Re 185.9549861(13) 3.7186(5) d EC to 186W; ß- to 186Os 1- 1.739 1465.07 -
187Re 186.9557531(15) 41.2(2)E+9 y ß- to 187Os; a to 183Ta 5/2+ 3.2197 1473.15 62.6
188Re 187.9581144(15) 17.0040(22) h ß- to 188Os 1- 1.788 1481.22 -
189Re 188.959229(9) 24.3(4) h ß- to 189Os 5/2+ N/A 1489.3 -
190Re 189.96182(16) 3.1(3) min ß- to 190Os (2)- N/A 1488.06 -
191Re 190.963125(11) 9.8(5) min ß- to 191Os (3/2+,1/2+) N/A 1496.14 -
192Re 191.96596(21)# 16(1) s ß- to 192Os N/A N/A 1504.22 -
193Re 192.96747(21)# 30# s [>300 ns] Unknown 5/2+# N/A 1512.3 -
194Re 193.97042(32)# 2# s [>300 ns] Unknown N/A N/A 1511.06 -