Jul 12 2013
Topics Covered
Introduction
Chemical Properties
Physical Properties
Mechanical Properties
Thermal Properties
Applications
Introduction
Gallium is a chemical element with Ga as its symbol. It belongs to group 13, periodic number 4 of the periodic table. Its atomic number is 31.
Gallium is a blue-gray metal with a orthorhombic crystalline structure. It is solid at normal room temperatures, but turns to liquid when slightly heated. Solid gallium can even be cut with a knife as it is so soft. It is stable in air and water; however dissolves in acids and alkalis.
Gallium is a byproduct during burning of coal, aluminum and zinc production. It also occurs in trace amounts in sphalerite, germanite, diaspore, and bauxite.
Chemical Properties
The chemical properties of gallium are provided in the table below.
|
Chemical Data |
|
CAS number |
7440-55-3 |
|
Thermal neutron cross section |
2.8 barns/atom |
|
Electrode potential |
-0.520 V |
|
Ionic radius |
0.620 Å |
|
Electronegativity |
1.81 |
|
X-ray absorption edge |
1.195 Å |
|
Electrochemical equivalent |
2.45 g/A/h |
Physical Properties
The following table discusses the physical properties of gallium.
|
Properties |
Metric |
Imperial |
|
Density (@20°C/68°F) |
5.1 g/cm3 |
0.184 lb/in3 |
|
Melting point |
29.78°C |
85.60°F |
|
Boiling point |
2204°C |
3999°F |
Mechanical Properties
The mechanical properties of gallium are tabulated below.
|
Properties |
Metric |
Imperial |
|
Hardness, Vickers |
50 |
50 |
Thermal Properties
The thermal properties of gallium are tabulated below.
|
Properties |
Metric |
Imperial |
|
Thermal expansion co-efficient (@20-100°C/68-212°F) |
58 µm/m°C |
32.2 µin/in°F |
|
Thermal conductivity |
41 W/mK |
285 BTU in/hr.ft².°F |
Applications
The following are the application areas of gallium:
-
In mirrors
-
To form low-melting alloys
-
In high temperature thermometers
-
Bright, highly reflective surface coating for on glass
-
In LEDs for electronic display and watches
-
Semiconductor components