Rhenium, Re

Rhenium is a chemical element with the symbol Re and atomic number 75. A silvery-white, rare, heavy, polyvalent transition metal, rhenium resembles manganese chemically and is used in some alloys. Rhenium is obtained as a by-product of molybdenum refinement and rhenium-molybdenum alloys are superconducting. It was the last naturally occurring element to be discovered and belongs to the ten most expensive metals on Earth (over US$ 7500.-/kg).

Rhenium is a silvery white metal, lustrous, and has one of the highest melting points of all elements, exceeded by only tungsten and carbon. It is also one of the most dense, exceeded only by platinum, iridium and osmium. Rhenium has the widest range of oxidation states of any known element: -3, -1, 0, +1, +2, +3, +4, +5, +6 and +7. The oxidation states +7, +6, +4, +2 and -1 are the most common.

Its usual commercial form is a powder, but this element can be consolidated by pressing and resistance-sintering in a vacuum or hydrogen atmosphere. This procedure yields a compact shape that is in excess of 90 percent of the density of the metal. When annealed this metal is very ductile and can be bent, coiled, or rolled. Rhenium-molybdenum alloys are superconductive at 10 K; tungsten-rhenium alloys are also superconductive, around 4-8 K depending on the alloy. Rhenium metal superconducts at 2.4 K.

Technical Data
Symbol Re Ionic radius(6-coordinate)/pm IV 63
Atomic number 75 Density (25°C)/gcm-3 21
No. of naturally occurring isotopes 2 Melting point/ °C 3180
Atomic weight 186.207 Boiling point / °C -5650
Electronic configuration [Xe]4f145d56s2 ΔHfus/kJmol-1 34(+/-4)
Metal radius(.12-coordinate)/pm 137 ΔHvap/kJmol-1 704
Ionic radius(6-coordinate)/pm VII 53 ΔHf(monoatomic gas)/kJmol-1 779(+/-8)
Ionic radius(6-coordinate)/pm VI 55 Electrical resistivity (20°C)/μohm cm 19.3
Ionic radius(6-coordinate)/pm V 58 Electronegativity χ 1.9
Evaporation Techniques
Temperature (oC) @Vap. Pressure Techniques Remarks
10-8 Torr 10-6 Torr 10-4 Torr Electron Beam Crucible Coil Boat
1928 2207 2571 Poor - - - Fine wire will self-evaporate

Evaporation Materials
R1-5000-M Ingot (Please ask for sizes)
R1-5001-M pellets 6mm diameter x 3mm long
R1-5002-M pellets 6mm diameter x 6mm long
R1-5003-M pieces 3-6 mm

The foils are available in either rectangular or circular shape. Please enter width and length or diameter of the required foil.

Foil
R1-3003-F 0.004" (0.1mm)
R1-3007-F 0.008" (0.2mm)
Powder
R1-10000-P -325 mesh
Rods
R1-2000-R 0.0625" (1.58mm)
R1-2001-R 0.125" (3.175mm)
R1-2002-R 0.250" (6.35mm)
R1-2003-R 0.500" (12.7mm)
R1-2004-R 0.625" (15.88mm)
R1-2005-R 0.750" (19.05mm)
R1-2006-R 1" (25.4mm)
Sheet
R1-4001-S
R1-4002-S
R1-4003-S
R1-4004-S
R1-4006-S
R1-4008-S
R1-4009-S
R1-4010-S
R1-4011-S
R1-4012-S
R1-4013-S
Wire
R1-1000-W 0.005" (0.127mm)
R1-1003-W 0.008" (0.203mm)
R1-1007-W 0.020" (0.5mm)
R1-1009-W 0.040" (1.0mm)
R1-1011-W 0.060" (1.5mm)
R1-1013-W 0.080" (2.0mm)