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(Anglo-Saxon lead; L. plumbum) Long known, mentioned in Exodus. The alchemists believed
lead to be the oldest metal and associated with the planet Saturn. Native lead occurs in
nature, but it is rare.
Lead is obtained chiefly from galena (PbS) by a roasting process. Anglesite, cerussite,
and minim are other common lead minerals.
Lead is a bluish-white metal of bright luster, is very soft, highly malleable, ductile,
and a poor conductor of electricity. It is very resistant to corrosion; lead pipes bearing
the insignia of Roman emperors, used as drains from the baths, are still in service. It is
used in containers for corrosive liquids (such as sulfuric acid) and may be toughened by
the addition of a small percentage of antimony or other metals.
Natural lead is a mixture of four stable isotopes: 204Pb (1.48%), 206Pb (23.6%), 207Pb
(22.6%), and 208Pb (52.3%). Lead isotopes are the end products of each of the three series
of naturally occurring radioactive elements: 206Pb for the uranium series, 207Pb for the
actinium series, and 208Pb for the thorium series. Twenty seven other isotopes of lead,
all of which are radioactive, are recognized.
Its alloys include solder, type metal, and various antifriction metals. Great
quantities of lead, both as the metal and as the dioxide, are used in storage batteries.
Much metal also goes into cable covering, plumbing, ammunition, and in the manufacture of
The metal is very effective as a sound absorber, is used as a radiation shield around
X-ray equipment and nuclear reactors, and is used to absorb vibration. White lead, the
basic carbonate, sublimed white lead, chrome yellow, and other lead compounds are used
extensively in paints, although in recent years the use of lead in paints has been
drastically curtailed to eliminate or reduce health hazards.
Lead oxide is used in producing fine "crystal glass" and "flint
glass" of a high index of refraction for achromatic lenses. The nitrate and the
acetate are soluble salts. Lead salts such as lead arsenate have been used as
insecticides, but their use in recent years has been practically eliminated in favor of
less harmful organic compounds.
Care must be used in handling lead as it is a cumulative poison. Environmental concerns
with lead poisoning has resulted in a national program to eliminate the lead in gasoline.
Sources: CRC Handbook of Chemistry
and Physics and the American Chemical Society.
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