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 |
|
|
|
|
|
|
LEAD (Anglo-Saxon lead) Pb (L. plumbum); at. wt.
207.2; at. no.82; m.p. 327.5020C; b.p. 17400C; sp. gn 11.35
(200C); valence 2 or 4. Long known; mentioned in Exodus.
The alchemists believed lead to be the oldest metal and
associated it 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 (PbSO4), Cerrusite
(PbCO3), and Minim (Pb3O4) are other common lead
minerals. Lead is a bluish-white metal of bright luster, very
soft, highly malleable, is 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 as containers for cor-
rosive liquids, such as in sulfuric acid chambers, and it may
be toughened by the addition of a small percentage of
antimony or other metals. Natural lead is a mixture of
four stable isotopes: Pb204 (1.48%), Pb206 (23.6%), Pb207
(22.6%), and Pb208 (52.3%). Lead isotopes are the end pro-
ducts of each of the three series of naturally occurring radio-
active elements: Pb206 for the uranium series, Pb207 for the
actinium series, and Pb208 for the thorium series. Twenty-five
other isotopes of lead, all of which are radioactive, are recog-
nized. Its alloys include solder, type metal, and various anti-
friction 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 lead tetraethyl, used as an anti-knock com-
pound in gasoline. The metal is very effective as a sound
absorber, is used as a radiation shield around x-ray equip-
ment and nuclear reactors, and is used to absorb vibration.
White lead, the basic lead carbonate, sublimed white lead
(PbSO4), chrome yellow (PbCrO4), red lead (Pb3O4) and
other lead compounds are extensively used in paints. 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
THE ELEMENT~CDntiflue)
as lead arsenate, have been used as insecticides, but their
use in recent years has been practically eliminated and
replaced with less harmful organic compounds. Care must
be used in handling lead as it is a cumulative poison.
© 1999 F. Davies
Delphi O.E.M. Co.
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