Atomic number: 36

Symbol: Kr

Category: noble gas

Density at 25°C: gas

This is a noble gas, like the other gases above it in the periodic table, it is a very stable gas too. There are essentially no normal reactions except for some very low temperature possibilities. Mostly it is used in lighting and cooling.


Electric discharge light with krypton. image: wikipedia

Use, natural applications or common combinations: 

  • Was used as standard for the distance of 1 metre.
  • Used in laser applications.
  • Lighting
  • Specialised cooling applications.
  • The name sounds awesome for superman's fictional birthplace.

Basic characteristics:

  • Standard atomic weight: 83.798(2)
  • Melting point:  -157.36 °C
  • Boiling point: -153.22 °C
  • Radioactivity: almost all stable naturally
    • 85Kr is a radioactive indication of nuclear weapons usage.
    • 86Kr was used as the standard of the metre.