Germanium – Properties and Applications

Chemical Formula

Ge

Topics Covered

Background
Basic Information
Occurrence
Production of Germanium
Isotopes
Health Aspects
Key Properties
Applications

Background

Russian Chemist Dmitri Mendeleev, who developed the periodic table, predicted that a new element will be discovered to fill an empty spot in the table. In 1886AD, Germanium was discovered by German chemist, Clemens Alexander Winkler.

In 1885, a new ore was found in a mine near Freiberg, Germany. The ore contained silver and sulfur. Winkler isolated a new element from the ore and named it as germanium. The name germanium is derived from Germany, which is the native country of Winkler.

Germanium is a metalloid like silicon and as such is used to make semiconductor devices.

Basic Information

Table 1. Basic Properties of Germanium

Name Germanium
Symbol Ge
Atomic number 32
Atomic weight 72.64 amu
Standard state solid at 298 K
CAS Registry ID 7440-56-4
Group in periodic table 14
Group name None
Period in periodic table 4
Block in periodic table p-block
Colour Grayish white
Classification Semi-metallic
Melting Point 1211.40 K (938.25°C or 1720.85°F)
Boiling Point 3106 K (2833°C or 5131°F)
Density 5.323 g/cm3
Number of Stable Isotopes 4
Ionization Energy 7.900 eV
Oxidation States +4, +2

Occurrence

Germanium is found in the Earth's crust. Argyrodite and germanite are the main germanium-containing minerals, with only African deposits of Germanite being regarded as significant.

Production of Germanium

Germanium is most commonly refined from by-products of non-ferrous (in particular zinc) production and from coal ash. Germanium concentrates are oxidised by heating in air and converted to GeCl4 using concentrated chlorohydric acid, which is then hydrolysed to form GeO2, which is in turn reduced in hydrogen at temperatures of 600-700°C to yield germanium.

Isotopes

Germanium comprises five naturally occurring isotopes that include germanium-70, germanium-72, germanium-73, germanium-74 and germanium-76. Their only application is in the manufacture of medical radioisotopes as follows:

  • Ge-74 to produce As-74
  • Ge-76 to produce As-77
  • Ge-74 to produce As-73
  • Ge-72 to produce As-72

Health Aspects

Germanium chloride (GeCl4) and germanium fluoride (GeF4 ) can cause irritation to the eyes, skin, lungs and throat.

Key Properties

The key properties of Germanium are:

  • It is a Gray-white brittle metal, is bright, shiny and silvery in color
  • Is brittle and breaks apart easily unlike other metals
  • It is a relatively inactive element
  • It is a poor conductor of electricity, can be classified as a semiconductor
  • It is insoluble with water and does not react with oxygen at room temperature
  • It dissolves in hot acids and with oxygen at high temperature
  • When finely divided, it becomes more active

Applications

The applications of Germanium are listed below:

  • Germanium's main use is to produce solid-state electronics, semiconductors and fiber optic systems.
  • As a phosphor in fluorescent lamps
  • It is used in infra red optics, in particular for thermal imaging in milatrya nd firefighting applications
  • Germanium is used to manufacture rectifiers, transistors and weapons-sighting systems and used as a fluorescent material.
  • Alloying agent
  • Germanium can also be used as a catalyst to produce plastics.

Source: AZoM.com

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