Atomic number: 32

Symbol: Ge

Category: metalloid

Density at 25°C: solid:  5.323 g·cm−3

Germanium is or was best known as part of the history of the transistor. In the early days almost all transistors were made from this element. Germanium is not found naturally in nature because it reacts too easily, but when isolated acts as a semi conductor.

Close-up image of 12 grams of germanium crystal . image: adapted from wikipedia

Use, natural applications or common combinations: 

  • early transistors, now as electronics alloys with silicon
  • Fibre optics
  • catalyst for making PET plastics

Basic characteristics:

  • Standard atomic weight: 72.63(1)
  • Melting point: 938.25 °C
  • Boiling point: 2833 °C
  • Radioactivity:  all stable naturally
    • 76Ge is very slightly radioactive