Evening star. [volume] (Washington, D.C.) 1854-1972, 1953-02-06
Rure Rhenium Is IdeuI
AS q Heut-Resistunt
Recreuted Ghost Elements
Muy Become Wonder Metals
BY Thomas R. Henry

By Thomas R. Henry
A ghost element, dead on earth for
a billion years and now reSurrected by
the strange alchemy of the atomic age,
and its immortal, Silver-like twin sister
promise to become new wonder metals
in science and industry.
Most significant of the two is the
metal rhenium, one of the two or
three scarcest materials that went into
the mixture of elements which con-
Stitute the crust of the earth There
is about a thirty thousandth of an
ounce per ton in the surface rocks, cal
culated as an average. It is the fourth
heaviest of the metals. so hard that it
can be rolled only when red hot, es-
sentially rust proof, extremely resistant
to acids. It has the second highest
melting point of all the metals, 3,170
centigrade. This is exceeded only by
tungsten at $3.50.
The total world production is few
hundred pounds year. It cost $50 900
to extract the first gram Is years ago.
The second gram cost 81, and this
has remained the stable price ever
since.
1OeaI 1Or LlgnC BUILDS.
It now has developed that rhenium
filaments are nearly ideal for light
bulbs and vacuum tubes. With nearly
the same resistance to heat as tungsten,
these f1laments don't sputter-that is,
the glass of the bulbs and tubes can
remain in use about twice as long with
out blackening on the insides as can
these with tungsten filaments.
A remarkable property of rhenium
makes it indispensable for those in
credibly delicate heat measuring in
struments, thermocouples = in which
fine wires of two different elements are
Joined. Heat falling on the junction of
the two sets up an electric current
which is direct measure of the
amount of heat. Previous thermo-
couples have measured temperature SO
precisely that it has been possible, for
example, to determine the temperature
on the surface of the moon or Mars.
Instruments where rhenium wires are
paired with platinum have proved four
fold as sensitive as those made Of any
other couplings. Such thermocouple
operates at heats up to 1900 centigrade.
ThermocoupleS are an essential part Of
some of the most complicated me-
chaniSmS.
When rhenium is deposited on glass.
optical mirrors are produced which are
of high quality and probably will last
forever. 1t has a high value for vari-
Gus metallic alloys.
Nearly Indistinguishable.
The twin sister specifically is nearly
indistinguishable. This metal is tech
nicium, first produced artificially in the
University of California cyclotron in
1910 and now being made in gram lots
by the Atomic Energy Commission at
Oak Ridge So little is available, as
yet. possible uses have not been deter
mined.
Presumably, at the beginning of time
on earth, there were equal amounts of
rhenium and technicium in the "sun
mixture" of 80 elements out of which
this planet was made. But technicium
was mildly radioactive. It had half
life of approximately a million years,
at the end of which time half of that
originally present had been transmitted
into the far commoner but somewhat
similar, element molybdenum. In the
next million years half the remainder
had undergone similar tranSforma-
ton. There have been at least 1000
million years. SO the few thousand tons
originally present must have disap-
peared long since. There hardly can
be, at the best, more than few grains
left in the entire planet.
Back in 1859 the Russian chemist
Mendeleeff predicted the existence of
both rhenium and technicium because,
in the table of elements he constructed.
there were vacant places where they
would fit. It was not until 1925, how
ever, that husband-and-wife team In
Germany, DR.. and Mrs. Walter Nod
dack, claimed to have isolated both the
elusive elements. They named the first
rhenium, for the Rhine, and the other
masurium. from the MaSurian Lakes
region of East Prussia which had been
the scene of a great victory over the
Russians.
No Doubt About Rhenium.
So far as rhenium was concerned,
there never was any doubt. Within q
year or so they had been able to ex-
tract almost an ounce Of the silvery
metal. At the time they furnished a
small sample to DR.. William F. MeggerS
of the United States Bureau of Stand
ards. DR.. Meggers is probably the
worlds foremost authority on the
spectra of elements. Every element
when heated to the point of lumines-
cence, emits light of specific wave
lengths which are peculiar to that ele-
ment alone. To some extent these wave
lengths can be predicted. DR.: Meggers
determined in preliminary study that
the material provided by the Noddacks
was unquestionably rhenium.
At the same time the German chem
lists wrote DR.. Meggers that they were
accommodating a minute supply OF
masurium, predicted by the Russian
chemist under the name of eka-
manganese. They would send him some.
they said, as soon as any was avail.
able.
It now is fairly clear that the Nod
dacks were mistaken. The promised
sample never came. II they had any
of the element. and theoretically this
is close to impossible, it long since has
disappeared. The best that the Ger
mans could claim was rhenium, last Of
the earth's stable elements to be dis