Jul 11 2013
Topics Covered
Introduction
Chemical Properties
Physical Properties
Mechanical Properties
Thermal Properties
Applications
Introduction
Lead is a chemical element with Pb as its symbol. It belongs to group 14 of the periodic table and its atomic number is 82.
Lead has been in use for centuries. It is usually found in the ores of silver, zinc, and copper. This metal is soft, dense, and ductile, and is known to be malleable and corrosion resistant. When lead is cut, it is bluish-white in color; however on exposure to air it tarnishes to a dull grayish color.
Lead is a toxic element and has to be used and disposed with caution with minimal exposure to humans.
Chemical Properties
The chemical properties of lead are provided in the table below.
|
Chemical Data |
|
CAS number |
7439-92-1 |
|
Thermal neutron cross section |
0.17 barns/atom |
|
Electrode potential |
-0.126 V |
|
Ionic radius |
0.840 Å |
|
Electronegativity |
1.8 |
|
X-ray absorption edge |
0.14077 Å |
|
Electrochemical equivalent |
3.858 g/A/h |
Physical Properties
The following table discusses the physical properties of lead.
|
Properties |
Metric |
Imperial |
|
Density (@20°C/68°F) |
11.34 g/cm3 |
0.409 lb/in3 |
|
Melting point |
327°C |
621°F |
|
Boiling point |
1755°C |
3191°F |
Mechanical Properties
The mechanical properties of lead are tabulated below.
|
Properties |
Metric |
Imperial |
|
Tensile strength |
18 MPa |
2610 psi |
|
Poisson’s ratio |
0.42 |
0.42 |
|
Modulus of elasticity |
14 GPa |
2030 ksi |
|
Shear modulus |
4.90 GPa |
711 ksi |
|
Hardness, Brinell |
4.2 |
4.2 |
|
Hardness, Vickers |
5 |
5 |
Thermal Properties
The thermal properties of lead are tabulated below.
|
Properties |
Metric |
Imperial |
|
Thermal expansion co-efficient (@20-100°C/68-212°F) |
29.1 µm/m°C |
16.2 µin/in°F |
|
Thermal conductivity |
33 W/mK |
229 BTU in/hr.ft².°F |
Applications
The following are the application areas of lead:
-
Ballasts
-
Counterweights
-
Sound insulation
-
Inertial components
-
In lead-acid batteries
-
Ammunition and armors
-
As a coloring element in ceramic glazes
-
As a protective glass of computer and TV screens to shield the viewer from radiation.
Lead can be formed into many useful compounds. Some are listed below with their specific application areas:
-
Lead monoxide - to make some types of glass, and as a paint pigment
-
Lead dioxide - In lead-acid storage batteries
-
Trilead tetraoxide - to make a reddish-brown paint that is designed to prevent rust on outdoor steel structures
-
Lead arsenate – used in insecticide
-
Lead nitrate - to make fireworks and other pyrotechnics