Dr. N.C. Beese studying an experimental Tellurium vapor discharge lamp through a glass filter in the Research Laboratory of the Westinghouse Lamp Division, Westinghouse Electric & Manufacturing Co., Bloomfield, N.J.
Because it has a continuous spectrum like the sun and unlike other materials used in vapor lamps, tellurium vapor is the object of this inquisitive scientist's study.
He is Dr. N.C. Beese of the Westinghouse Lamp Division at Bloomfield, N.J. The tellurium vapor lamp is one of many new sources of lighting being studied by scientists the world over. Tellurium is a semi-metallic element.
Atomic Radius: 143.2 pm
Atomic Symbol: Te
Melting Point: 449.5 deg C
Atomic Weight: 127.60
Boiling Point: 988 deg C
Electron Configuration: [Kr]5s24d105p4
Oxidation State: 6, 4, -2
(L. tellus: earth) Discovered by Muller von Reichenstein in 1782;
named by Klaproth, who isolated it in 1798.
Tellurium is occasionally found native, but is more often found
as the telluride of gold (calaverite), and combined with other metals.
It is recovered commercially from anode muds produced during the
electrolytic refining of blister copper. The U.S., Canada, Peru,
and Japan are the largest Free World producers of the element.
Crystalline tellurium has a silvery-white appearance, and when pure
it exhibits a metallic luster. It is brittle and easily pulverized.
Amorphous tellurium is found by precipitating tellurium from a solution
of telluric or tellurous acid. Whether this form is truly amorphous,
or made of minute crystals, is open to question. Tellurium is a
p-type semiconductor, and shows greater conductivity in certain
directions, depending on alignment of the atoms.
increases slightly with exposure to light. It can be doped with
silver, copper, gold, tin, or other elements. In air, tellurium
burns with a greenish-blue flames, forming the dioxide. Molten tellurium
corrodes iron, copper, and stainless steel.
Tellurium and its compounds are probably toxic and should be handled
with care. Workmen exposed to as little as 0.01 mg/m3 of air, or
less, develop "tellurium breath," which has a garlic-like
Thirty isotopes of tellurium are known, with atomic masses ranging
from 108 to 137. Natural tellurium consists of eight isotopes.
Tellurium improves the machinability of copper and stainless steel,
and its addition to lead decreases the corrosive action of sulfuric
acid on lead and improves its strength and hardness. Tellurium is
used as a basic ingredient in blasting caps, and is added to cast
iron for chill control. Tellurium is used in ceramics. Bismuth telluride
has been used in thermoelectric devices.
Los Alamos National Laboratory - periodic tables