Rhenium

Images

Image

Attribution: Alchemist-hp

Animated Rhenium

History

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.

Sources

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.

Uses

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

Natural rhenium is a mixture of two stable isotopes. Twenty six other unstable isotopes are recognized.

General Info

AtomicNumber
75
Symbol
Re
Name
Rhenium

Atomic Info

Appearance
AtomicWeight
186.207(1)
Color
267DAB
ElectronicConfiguration
[Xe] 4f14 5d5 6s2
ElectronegativityInPauling
1.9
AtomicRadiusInPM
159
IonRadiusInPM
63 (+4)
VanDerWaalsRadiusInPM
IEinKJmol
760
EAinKJmol
-15
OxidationStates
-3, -1, 1, 2, 3, 4, 5, 6, 7
StandardState
solid
BondingType
metallic
MeltingPoint
3459
BoilingPoint
5869
Density
21.02
State
Transition metal
DiscoveredYear
1925