Lead (Pb) - Properties, Applications

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

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