H' at. wt. (natural) 1.007967
at. wt. (H') 1.007822
at. no. 1
m.p. - 259.140C
b.p. - 252.870C
density 0.08988 gm./l
density (liquid) 70.8 gm/i. (-2530C)
density (solid) 7016 gm/i. (-2620C)
valence 1.
Electronic configuration
| K |
L |
M |
N |
O |
P |
Q |
| 1 |
2 |
3 |
4 |
5 |
6 |
7 |
| s |
s p |
s p d |
s p d f |
s p d f |
s p d f |
s p d f |
| 1 |
|
|
|
|
|
|
RHENIUM (L. Rhenus, Rhine), Re; at. wt. 186.2; at. no.
75; m.p. 31800C; b.p. 56270C (est.'); sp. gr. 21.02 (200C);
valence - 1, 2, 3, 4, 5, 6, 7. 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 up660 kg. of molybdenite they were
able in 1928 to extract 1 gm. of rhenium.The price in 1928 was,
510,000/gm. Rhenium does not occur free in nature or as a
compound in a "distinct mineral species. It is, however,
widely 'spread thrdughout 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 molyb'-
denites contain from 0.002 to 0.2 % rhenium. More than
120,000 troy ounces of rhenium are now being produced
yearly in the United States. The total estimated free-world
reserve of rhenium metal is '100 tons. Natural rhenium is a
mixture of two stable isotopes. Eighteen other unstable
isotopes are recognized. Rhenium metal is prepared by.
reducing ammonium perrhenate with hydrogen at elevated
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 pro-
duces 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 spectro-
graphs and ion gages. Rhe'nium-molybdenum alloys are
superconductive at I 00K. Rhenium is also used as an
electrical contact material as it has good wear resistance
and with~tands arc corrosion. Thermocouples made of
B-27
Re-W are used for measuring temperatures lip to 2200"C,
and rhenium wire is used in photoflash lamps for photog-
raphy. Rhenium catalysts are exceptionally resistant to
pnisoning from nitrogen, sulfur, and phosphorus, and are
used 'for hydrogenation of fine chemicals, hydrocracking,
reforming, and the disproportionation of olefins. Rhenium
costs about 540/troy ounce. Little is 'known of its toxicity;
therefore it should be handled With care until more data
are available.
© 1999 F. Davies
Delphi O.E.M. Co.
All rights reserved
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