Cadmium (Cd) - Properties, Applications

Topics Covered

Introduction
Chemical Properties
Physical Properties
Mechanical Properties
Thermal Properties
Applications

Introduction

Cadmium is a soft, bluish white metal that can be easily cut with a knife. Its chemical symbol is Cd and its atomic number is 48. It has similar characteristics to zinc and mercury and it tarnishes when exposed to air. It is soluble in acids but insoluble in alkalis. Cadmium belongs to the d-block, period 5 of the periodic table.

Canada, USA, Mexico and Australia are leading producers of cadmium.

Chemical Properties

The chemical properties of cadmium are provided in the table below:

Chemical Data
CAS number 7440-43-9
Thermal neutron cross section 2.4 barns/atom
Electrode potential -0.403 V
Ionic radius 0.970 Å
Electro negativity 1.69
X-ray absorption edge 0.46408 Å
Electrochemical equivalent 2.09 g/A/h

Physical Properties

The following table discusses the physical properties of cadmium.

Properties Metric Imperial
Density 8.64 g/cm3 0.312 lb/in3
Melting point 321 °C 610 °F
Boiling point 767°C 1413°F

Mechanical Properties

The mechanical properties of cadmium are tabulated below.

Properties Metric Imperial
Tensile Strength 75 MPa 10900 psi
Modulus of elasticity 55.2 GPa 8010 ksi
Shear modulus 19.2 GPa 2780 ksi
Hardness, Brinell 16-24 16-24
Hardness, Vickers 22 22
Poissons Ratio 0.33 0.33

Thermal Properties

The thermal properties of cadmium are tabulated below.

Properties Metric Imperial
Thermal expansion co-efficient (@20-100°C/68-212°F) 30.0 µm/m°C 16.7 µin/in°F
Thermal conductivity 92.0 W/mK 638 BTU in/hr.ft².°F

Applications

The following are the application areas of cadmium:

  • Making of nickel-cadmium batteries
  • Pigments, coatings and plating
  • Stabilizers in manufacture of plastics
  • Electroplating of steel
  • Nuclear reactors.

Cadmium compounds are used as black and white television phosphors, photoconductive surface in photocopier drums, paint pigments and in PVC.

Comments

  1. Angus McDonald Angus McDonald Canada says:

    I am told by my naturopath that I have toxic levels of cadmium in my body. Subsequent testing has found that my kidney function is poor. I am learning that cadmium is used in steel plating, electrical contacts, and as a stabilizer in olastics such as pvc - all things I am frequently in contact with, handling, gluing and cutting - as an electrician. I'd like to know if my concerns are warranted, that this is the source of my body's high cadmium levels. Thanks.

    • Christina Gustin Christina Gustin United States says:

      You have listed valid ways of exposure to cadmium. You may want to work with breathing protection when cutting, soldering or welding metals or certain plastics. If you are a user of tobacco products, this is another way to be exposed.

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of AZoM.com.

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