Krypton (Kr): IMPORTANT GAS FOR GLASS
The noble gas krypton is very difficult to extract from air. Correspondingly expensive, it is primarily used today as a filling gas in double glazed windows, where it provides significantly better insulation than the less expensive argon. Krypton is also used as a filling gas in Geiger counters for measuring radioactive radiation. Other applications take the form of krypton mixtures used in special lasers for performing eye surgery or manufacturing intricate semiconductor components.
The chemists William Ramsay and Morris William Travers had a hard time proving the existence of krypton as a new element. At first all they knew was that other similar elements must exist besides argon and helium. They finally discovered one in 1898 and named it krypton. Its name comes from the ancient Greek word “kryptos” – which means “the hidden one” – and refers to the search for this element.
The noble gas krypton is one of the rarest elements on Earth. Most of it occurs in the atmosphere. The share of krypton in the universe is greater. Scientists suspect that the interstellar matter whose momentum creates magnetic fields and radiation in interstellar space is rich in krypton.
Krypton played a special role in the definition of the meter: that unit of measure was initially defined by the international prototype meter – a platinum bar, the length of which was one ten-millionth of the distance between the North Pole and the Equator. Through more precise measurement methods, the official length of the meter was altered several times – and its definition was modified likewise.
At the start of the 20th century, the idea of using the wavelength of spectral lines to define the meter emerged. In the early 1950s, scientists developed the krypton-86 discharge lamp, which emitted light with the most stable and reproducible wavelength. Based on that new method, the meter was redefined in 1960. The definition of the meter that is still valid to this day was established in 1983 and is based on a path-time measurement of light in a vacuum.
|Mass fraction in the Earth’s atmosphere is 1.14 ppm|
- 152 °C
|- 157.36 °C|
|Very inert, thermodynamically unstable|