Krypton (Kr): Guide to Properties, Uses, and Quick Facts

Discover why a hidden gas shaped the meter and modern lasers

Krypton belongs to Group 18 of the periodic table. It is monatomic at standard conditions and is mostly recovered from liquefied air. Its sharp emission lines made krypton-86 the basis for the international definition of the meter from 1960 to 1983. Though chemically inert in most conditions, krypton can form a few compounds with fluorine that have scientific and laser applications.

In this article, we summarize krypton’s key properties, natural occurrence, common uses, and the notable compounds chemists have prepared.

Properties of krypton

What does krypton look like?

Krypton is a colorless, odorless gas under normal conditions. When electrically excited in a discharge tube, it emits multiple sharp spectral lines and a characteristic whitish glow used in photography and lighting effects.

Will we ever run out of krypton?

Krypton is a trace atmospheric gas, roughly 1 part per million by volume. It is isolated by fractional distillation of liquefied air. Because it is present only at trace levels, supply is linked to industrial air separation output, but there is no immediate scarcity risk for its current niche uses.

Can krypton be recycled

Krypton gas used in sealed systems can be recovered and reused. Recycling and careful capture from industrial processes help conserve supplies for specialized applications such as lasers and lighting.

Where can krypton be found?

Krypton is not found in minerals. It occurs in Earth’s atmosphere at trace levels and can also appear in small amounts in meteorites. Commercial krypton is obtained by cooling air to a liquid, then separating components by fractional distillation and further purification.

Is krypton expensive?

Krypton is more costly than common atmospheric gases because of its low concentration and the energy required to separate it. Pricing depends on purity, quantity, and the market for industrial gases.

Does krypton have a biological role?

Krypton has no known biological role. It is classified as not necessary for life and has no recognized biological benefits.

What is krypton used for?

• Lighting: Krypton is used in some fluorescent and incandescent lamps and in photographic flash lamps to achieve bright, white light.
• Lasers: Krypton fluoride and krypton ion lasers have specialized uses in research, lithography, and high-power light sources.
• Metrology and tracing: A spectral line of krypton-86 defined the meter between 1960 and 1983. Radioactive isotopes are used in tracer studies and leak detection.

What are the main compounds of krypton?

Chemists have isolated a small number of krypton compounds, especially with fluorine. The best known and most widely discussed is krypton difluoride. Links to additional compound pages are provided for further reading.

• Krypton difluoride (KrF₂) : the first and most studied krypton compound.
• Krypton compounds category : overview and related fluorides and salts.

Who discovered krypton?

Krypton was discovered in 1898 by Sir William Ramsay and Morris W. Travers. They isolated a small volume of the gas during experiments on liquefied air on May 30, 1898.

Is krypton dangerous?

Krypton is chemically inert in normal conditions and is not toxic. As an asphyxiant at high concentrations it can displace oxygen in confined spaces, so standard precautions for inert gases apply.

Fun facts about krypton

• The name comes from the Greek word kryptos, meaning hidden, reflecting its trace presence in air.
• From 1960 to 1983 a spectral line of krypton-86 was used to define the international meter.
• Although generally inert, krypton forms compounds with fluorine under extreme conditions, and krypton fluoride has been used as a laser medium.

Scientific data verified from the Royal Society of Chemistry, Encyclopaedia Britannica, and the Minerals Education Coalition.