Jul 11 2013
Topics Covered
Introduction
Chemical Properties
Physical Properties
Mechanical Properties
Thermal Properties
Applications
Introduction
Manganese is a pinkish-gray, chemically active element with Mn as its symbol. It belongs to group 7, periodic number 4 of the periodic table. Its atomic number is 25.
Manganese is obtained from the minerals pyrolusite and rhodochriste. It is a hard and very brittle metal that reacts with water and dissolves in dilute acids. The metal tends to rust like iron when exposed to water.
Leading producers of manganese are Australia, Brazil, South Africa, Gabon and India.
Chemical Properties
The chemical properties of manganese are provided in the table below.
Chemical Data |
CAS number |
7439-96-5 |
Thermal neutron cross section |
12.6 barns/atom |
Electrode potential |
-1.05 V |
Ionic radius |
0.460 Å |
Electronegativity |
1.55 |
X-ray absorption edge |
1.896 Å |
Electrochemical equivalent |
0.684 g/A/h |
Physical Properties
The following table discusses the physical properties of manganese.
Properties |
Metric |
Imperial |
Density |
7.44 g/cm3 |
0.269 lb/in3 |
Melting point |
1247 °C |
2277°F |
Boiling point |
2061 °C |
3742°F |
Mechanical Properties
The mechanical properties of manganese are tabulated below.
Properties |
Metric |
Imperial |
Tensile strength |
496 MPa |
71900 psi |
Yield strength |
241 MPa |
35000 psi |
Poisson’s ratio |
0.35 |
0.35 |
Modulus of elasticity |
159 GPa |
23100 ksi |
Shear modulus |
76.4 GPa |
11100 ksi |
Hardness, Brinell |
460 |
460 |
Hardness, Vickers |
500 |
500 |
Hardness, Rockwell A |
75 |
75 |
Hardness, Rockwell C |
48 |
48 |
Thermal Properties
The thermal properties of manganese are tabulated below.
Properties |
Metric |
Imperial |
Thermal expansion co-efficient (@20-100°C/68-212°F) |
22.8 µm/m°C |
12.7 µin/in°F |
Thermal conductivity |
1.64 W/mK |
11.4 BTU in/hr.ft².°F |
Applications
Almost 90% of the manganese produced annually is used in the production of steel.
The following are the application areas of manganese:
-
To depolarize dry cells
-
As an alloying component in a wide variety of steel and other alloys
-
To provide glass an amethyst color and to provide color to amethyst gemstones
Manganese can be formed into many useful compounds. Some are listed below with their specific application areas:
-
Potassium permanganate - used as a disinfectant
-
Manganese oxide - in fertilizers and ceramics
-
Manganese carbonate – as a starting material for making other manganese compounds
-
Manganese dioxide - as a catalyst.