Krypton
Kr

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General Characteristics Health Hazards Material Recommendations
A colorless, nonflammable and odorless gas. Non reactive. A Simple asphyxiant Normal materials can be used.
TLV-TWA Flammable Limits DOT Class / Label
None Established Nonflammable 2.2 / Nonflammable
Molecular Weight Specific Gravity Specific Volume
83.8 2.899 @ 70 F 4.6 cu.ft./lb @ 70 F
CGA Valve Outlet CAS Registry No. UN Number
580 7439-90-9 1056
National Stock Number (NSN) Applicable to Krypton MIL Specs/ Fed Specs
MSDS for Krypton


Grade
Part #
Purity Minimum Cylinder
Size
Volume
Liters
Pressure
@ 70 F
Comments
Research
422900
99.995% 049
044
016
007
002
LBS
7500
5000
1000
500
100
50
57.5
38.3
7.7
3.85
0.77
0.38

None


Uses: Krypton has some use in the lighting and electronic industry. A radioactive isotope of krypton, Kr85, is widely used in the medical field in heart shunt studies, and as a triggering agent in discharge type electronic tubes.

General

Krypton is named from the Greek word kryptos, "hidden." Traces of krypton are present in minerals and meteorites, but the usual commercial source is the atmosphere, which contains 1.14 parts per 106 by volume. Krypton also is formed by the nuclear fission of uranium triggered by slow neutrons: this source may be expected to become increasingly important because of the growing number of fission-power plants. Krypton has isotopes of every mass number from 74 through 95; six, with mass numbers 78, 80, 82, 83, 84, and 86, are stable. After it has been stored a few days, krypton obtained by nuclear fission contains only one radioactive isotope, krypton-85, which has a half-life of about 10 years, because all the other radioactive isotopes have half-lives of three hours or less. (The half-life is the length of time during which one-half of
any original amount of an unstable substance decays.)

Because its boiling point is about 30 C higher than those of the major constituents of air, krypton is readily separated from liquid air by fractional distillation; it accumulates along with xenon in the least volatile portion. These two gases are further purified by adsorption onto silica gel, redistillation, and passage over hot titanium metal, which removes all impurities except other noble gases.

(Kr), chemical element, rare gas of Group 0 (noble gases) of the periodic table, forming very few chemical compounds. About three times heavier than air, krypton gas is colourless, odourless, and tasteless. Although traces are present in meteorites and minerals, krypton is more plentiful in the Earth's atmosphere, which contains 1 part krypton in about 900,000. The element was discovered (1898) by the British chemists Sir William Ramsay and Morris W. Travers in the residue left after a sample of liquid air had boiled almost entirely away. Krypton is produced on a small commercial scale by fractional distillation of liquid air.

Krypton is used in certain fluorescent lamps and in a flash lamp employed in high-speed photography. Radioactive krypton-85 is useful for detecting leaks in sealed containers, with the escaping atoms detected by means of their radiation.

Krypton gas liquefies at -152.30° C (-242° F) and freezes 4 C lower. When a current of electricity is passed through a glass tube containing krypton at low pressure, a bluish white light is emitted. The wavelength of an orange-red component of light emitted by stable krypton-86, because of its extreme sharpness, served as the international standard for the metre from 1960 to 1983.  (One metre equals 1,650,763.73 times the wavelength of this line.)