| Rhenium - Re
CAS: 7440-15-5 Description: Silvery-white with a metallic luster Classification: Transition Metal Date of Discovery: 1925 Discoverer: Walter Noddack Name Origin: Latin Rhenus, "Rhine" |
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Atomic Number: 75
Number of Neutrons: 111 Atomic Mass: 186.207(1) amu Melting Point: 3186 °C Boiling Point: 5596 °C Density (293 K): 21.02 g/cm3 Atomic volume: 8.85 cm3/mol Electrical resistivity: 0.0542 10-6/cm 
Thermal conductivity: 0.479 W/cmK Enthalpy of atomization: 791 kJ/mol (est.) Enthalpy of vaporization: 715.0 kJ/mol Enthalpy of fusion: 33.20 kJ/mol Specific heat capacity: 0.13 J/gK |
Energy levels: 2-8-18-32-13-2
Electron configuration: [Xe]4f 145d56s2 Crystal Structure: Hexagonal Atomic radius: 1.97 Å Covalent radius: 1.28 Å Oxidation States: ±1, +2, +3, +4, +5, +6, +7 Electronegativity, Pauling: 1.9 Electron affinity: 0.15 eV First ionization energy: 7.88 eV 2nd ionization energy: 3rd ionization energy: Polarizability: 9.7 10-24cm3 |
| Isotope | Natural Abundance | Atomic Mass | Half-life | Decay Mode | Spin |
| 160Re | 159.981 | 0.8 ms | p;  |
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| 161Re | 160.978 | 0.01 s | |
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| 162Re | 161.9757 | 0.10 s | |
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| 163Re | 162.9721 | 0.26 s |  +, EC; |
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| 164Re | 163.9704 | 0.9 s | +, EC; |
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| 165Re | 164.9671 | 2 s | +, EC; |
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| 166Re | 165.9651 | 2.5 s | +, EC; |
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| 167mRe | 6.2 s | , EC |
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| 167Re | 166.9626 | 3.4 s | +, EC; |
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| 168Re | 167.9616 | 4.4 s | +, EC; |
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| 169mRe | 8.1 s | - |
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| 169Re | 168.9588 | 16 s | |||
| 170Re | 169.9582 | 9.2 s | +, EC |
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| 171Re | 170.9555 | 15.2 s | EC | ||
| 172mRe | 55 s | +, EC |
(2) | ||
| 172Re | 171.9553 | 15 s | +, EC |
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| 173Re | 172 | 2.0 m | EC | ||
| 174Re | 173.9521 | 2.4 m | +, EC |
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| 175Re | 174.9514 | 5.8 m | +, EC |
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| 176Re | 175.9516 | 5.3 m | +, EC |
(3+) | |
| 177Re | 176.9503 | 14 m | EC; + |
(5/2-) | |
| 178Re | 177.9509 | 13.2 m | +; EC |
(3) | |
| 179Re | 178.9500 | 19.7 m | EC; + |
(5/2+) | |
| 180Re | 179.95079 | 2.45 m | EC; + |
1- | |
| 181Re | 180.95006 | 20 h | EC | 5/2+ | |
| 182mRe | 12.7 h | EC | 2+ | ||
| 182Re | 181.9512 | 2.67 d | EC | (7+) | |
| 183Re | 182.95082 | 70 d | EC | (5/2+) | |
| 184mRe | 165 d | IT; EC | 8+ | ||
| 184Re | 183.95252 | 38 d | EC | 3- | |
| 185Re | 37.40(2) | 184.952955 | Stable | (5/2+) | |
| 186mRe | 2.0 x 105 y | IT | 8+ | ||
| 186Re | 185.954986 | 3.718 d | -; EC |
1- | |
| 187Re | 62.60(2) | 186.955751 | 4.4 x 1010 y | - |
5/2+ |
| 188Re | 187.958112 | 16.94 h | - |
1- | |
| 189Re | 188.959228 | 24 h | - |
(5/2+) | |
| 190mRe | 3.0 h | -; IT |
(6-) | ||
| 190Re | 189.9618 | 3.0 m | - |
(2-) | |
| 191Re | 190.96312 | 9.7 m | - |
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| 192Re | 191.9660 | 16 s | - |
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Discovery of rhenium is generally attributed to Noddack, Tacke, and Berg, who announced in 1925 they had detected the element in platinum ores and columbite. They also found the element in gadolinite and molybdenite. By working up 660 kg of molybdenite they were able in 1928 to extract 1 g of rhenium. The price in 1928 was $10,000/g. 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 molybdenite roaster-flue dusts obtained from copper-sulfide ores mined in the vicinity of Miami, Arizona, and elsewhere in Arizona and Utah. Some molybdenites contain 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. Natural rhenium is a mixture of two isotopes, one of which has a very long-half-life. Thirty-nine other unstable isotopes are recognized. Rhenium metal is prepared by reducing ammonium perrhenate with hydrogen at elevated tempemtures. 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. It has other useful properties. The usual commercial form of the element is a powder, but it can be consolidated by pressing and
resistance-sintering in a vacuum or hydrogen atmosphere. This produces a compact shape in excess of 90% 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. It is widely used for filaments for mass spectrographs and ion gages. Rhenium-molybdenum alloys are superconductive at 10 K.
Rhenium is also used as an electrical contact material as it has good wear resistance and withstands arc corrosion. Thermocouples made of Re-W are used for measuring temperatures up to 2200 °C, and rhenium wire has been 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, hydrocracking, reforming, and disproportionation of olefins. Little is known of its toxicity; therefore, it should be handled with care until more data are available.
LINKS: Casey Group: Locked Carbene Complexes Casey Group: Rhenium Dimer Halide Structure Database: Rhenium-Halide Frameworks Information from Reade Information, data sheet and standard forms Minerals Containing Rhenium Rhenium Alloys Home Page Rhenium Oxide crystal lattice Uses in high temperature environments Return
Sources for the information on this website include: Lide, David R., ed. CRC Handbook of Chemistry and Physics, 78th Ed., 1997-1998. |
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