Calcium (Ca) - Properties, Applications

Topics Covered

Chemical Properties
Physical Properties
Mechanical Properties
Thermal Properties


Calcium is the third most abundant metal in the earth’s crust. It is trimorphic in structure and its hardness is greater than that of sodium. It is less chemically reactive than alkaline metals. The atomic number of calcium is 20 and is represented by Ca.

The distribution of calcium is very wide; it is available in almost all environments across the globe. It is essential for the growth of plants and animals. It is not available alone in nature, it is found in the form of limestone, gypsum and fluorite. It is the most abundant metal present in the human body, being the main constituent of bones and teeth. Aquatic life is affected by the presence of its compound, calcium phosphide.

Chemical Properties

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

Chemical Data
CAS number 7440-70-2
Thermal neutron cross section 0.43 barns/atom
Electrode potential -2.80 V
Ionic radius 0.990 Å
Electro negativity 1
X-ray absorption edge 3.07016 Å
Electrochemical equivalent 0.747 g/A/h

Physical Properties

The following table discusses the physical properties of calcium.

Properties Metric Imperial
Density 1.54 g/cm3 0.055 lb/in3
Melting point 837-841 °C 1540-1550 °F
Boiling point 1484°C 2703°F

Mechanical Properties

The mechanical properties of calcium are tabulated below.

Properties Metric Imperial
Tensile Strength 110 MPa 16000 psi
Modulus of elasticity 23.4 GPa 3390 ksi
Shear modulus 7.38 GPa 1070 ksi
Hardness, Vickers 17 17
Elongation at Break 7% 7%
Poissons Ratio 0.31 0.31

Thermal Properties

The thermal properties of calcium are tabulated below.

Properties Metric Imperial
Thermal expansion co-efficient (@20°C/68°F) 22.15 µm/m°C 22.15 µin/in°F
Thermal conductivity 126 W/mK 874 BTU in/hr.ft².°F


The following are the application areas of calcium:

  • Reducing agent
  • Deoxidizer, desulfurizer and decarbonizer for various alloys
  • Making of cements and mortars
  • Making of cheese

Calcium compounds are used as manufacture of insecticides, paints, blackboard chalk, textile and fireworks.

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