Krypton

Krypton is a special gas in our air.

It has no smell and no color. Two men found it a long time ago. They found it in liquid air.

This gas helps make bright lights. Some lights use it to glow. It can help cameras take fast photos.

Krypton can even make a laser. A laser is a very strong beam of light. This gas is very quiet. It does not like to react with other things.

It is used in some windows too. It sits between the glass to keep heat in. This helps keep homes warm.

Krypton is a very useful thing. Can you see a bright light?

Krypton is a special gas found in our air. It has no color and no smell.

Scientists call it a noble gas. This means it is chemically inert. That is a way to say it does not like to react with other things.

Two men found krypton in 1898. Their names were William Ramsay and Morris Travers. They found it while studying liquid air.

Because of his work with noble gases, Ramsay won a Nobel Prize in 1904.

Krypton is very useful for making light. It can make bright, white light for cameras.

It also helps make energy-saving lamps. Some people use krypton between window panes to keep heat in.

Krypton can even make a laser. A laser is a very strong beam of light. One kind uses krypton fluoride. This gas helps make the beam. Scientists also use liquid krypton in big machines at CERN. These machines help study tiny particles. Even in space, there may be krypton waiting to be found.

Krypton is a special chemical element called a noble gas.

It is a gas that has no color and no smell. You can find it in our atmosphere in very small amounts. Scientists call it chemically inert. This means it does not like to react with other things. Most of the time, it just stays as it is. Because it is so steady, it is very useful for many jobs.

Krypton works in many ways to create light and power. In some lamps, it is mixed with other gases to make light. It can even be used in photography to make bright flashes.

Some lasers use a special mix called krypton fluoride. This works by having the gas absorb energy from a source. This causes the krypton to react with fluorine gas. This creates a temporary state that then releases a beam of light.

Two chemists discovered krypton in Britain in 1898.

Their names were William Ramsay and Morris Travers. They found it by looking at what was left after evaporating liquid air. They actually found neon using a similar way just a few weeks later. William Ramsay was a very important scientist. He won the Nobel Prize in Chemistry in 1904 for finding noble gases.

Krypton has been used to define how we measure things. From 1960 to 1983, the official meter was based on krypton-86.

Scientists used the wavelength of light from this gas to set the length. They looked at the light emitted in a vacuum. This replaced an old metal bar used in Sèvres. Krypton-86 was very helpful because it was easy to operate. It was a very precise way to measure the world.

You might see krypton working in things you use every day. It can be used as an insulating gas between window panes. This helps keep the temperature steady inside a house. Some space companies even use it as fuel for electric engines. It is also used in big machines at CERN to study particles. Scientists use liquid krypton because it helps them see things very clearly. Even in the deep ocean, isotopes of krypton can help date old groundwater.

Krypton is a chemical element with the symbol Kr and the atomic number 36. It belongs to a group of elements known as the noble gases.

These gases are characterized by being colorless and odorless. Krypton is also chemically inert, which means it is highly unreactive with other substances. It exists in our atmosphere in trace amounts, roughly 1 part per million. Because it is so stable, it is used in many specialized technological applications. It can act as a light source, a laser medium, or even a propellant in space.

One fascinating way krypton works is through the creation of an exciplex laser. In a krypton fluoride laser, the krypton gas absorbs energy from a specific source. This energy causes the krypton to react with fluorine gas. This reaction produces an exciplex, which is a temporary complex in an excited energy state. This complex then undergoes spontaneous or stimulated emission. This process reduces its energy state to a metastable ground state. The complex quickly dissociates into unbound atoms. This release of energy radiates at 248 nm, which is near the ultraviolet portion of the spectrum.

Krypton exists in several different forms, known as isotopes. Naturally occurring krypton in Earth's atmosphere is composed of five stable isotopes. There is also an isotope called 78Kr, which has an incredibly long half-life of 9.2×10^21 years. Because this decay takes so long, it is considered stable. Scientists also study unstable isotopes like 85Kr, which is produced by the fission of uranium and plutonium. This isotope has a half-life of 10.76 years. Another isotope, 81Kr, is produced by cosmic ray irradiation. It has a half-life of 230,000 years and helps scientists date groundwater that is between 50,000 and 800,000 years old.

The history of krypton is tied to the discovery of the noble gases.

In 1898, two chemists in Britain discovered the element. These were William Ramsay, a Scottish chemist, and Morris Travers, an English chemist. They found krypton by examining the residue left after evaporating nearly all the components of liquid air. Just a few weeks later, these same workers discovered neon using a similar method. For his work in discovering this series of noble gases, William Ramsay was awarded the 1904 Nobel Prize in Chemistry.

Krypton has played a vital role in how humans define measurements. From 1960 to 1983, the official definition of the meter was based on krypton-86.

Specifically, the meter was defined as 1,650,763.73 wavelengths of light emitted in a vacuum. This light corresponds to a specific transition between the 2p10 and 5d5 energy levels. This definition replaced the 1889 international prototype meter, which was a physical metal bar located in Sèvres. The use of krypton-86 was preferred because of its high power and the ease of operating krypton discharge tubes. This standard was eventually replaced in 1983 by a definition based on the speed of light.

There are many surprising ways krypton is used in modern science and industry. In particle physics, liquid krypton is used to build electromagnetic calorimeters. For example, the NA48 experiment at CERN uses about 27 tonnes of liquid krypton. It is chosen because it has a small Molière radius of 4.7 cm, which allows for excellent spatial resolution. In the field of space exploration, SpaceX Starlink uses krypton as a propellant for its electric propulsion systems. Even in medicine, the isotope krypton-81m is inhaled by patients to perform lung ventilation and perfusion scans using a gamma camera.

Krypton also has unique physical and chemical properties that scientists study under extreme conditions. When solid, krypton has a face-centered cubic crystal structure. Scientists have even grown krypton hydride crystals, known as Kr(H2)4, at pressures above 5 GPa. These crystals feature krypton octahedra surrounded by hydrogen molecules. While krypton is mostly unreactive, it can form compounds with fluorine under extreme conditions. It can also form polyatomic ions like the kryptonium ion, KrH+. These specialized chemical behaviors help researchers understand the fundamental rules of how atoms interact.