Element Krypton

Krypton ElementKrypton (from Ancient Greek: κρυπτός, romanized: kryptos “the hidden one”) is a chemical element with the symbol Kr and atomic number 36.
It is a colorless, odorless, tasteless noble gas that occurs in trace amounts in the atmosphere and is often used with other rare gases in fluorescent lamps. With rare exceptions, krypton is chemically inert.
Krypton, like the other noble gases, is used in lighting and photography. Krypton light has many spectral lines, and krypton plasma is useful in bright, high-powered gas lasers (krypton ion and excimer lasers), each of which resonates and amplifies a single spectral line.

Names and Identifiers

Chemical Formula:Kr
CAS:7439-90-9
Molecular Weight:83.79800 g/mol
EC Number :n/a
MDL Number:MFCD00151310
Color:colorless
Other Names:Cripto
PubChem CID:5416
IUPAC Name:Krypton
Inchl:InChI=1S/Kr
InChI Key:DNNSSWSSYDEUBZ-UHFFFAOYSA-N
Canonical SMILES:[Kr]
ICSC Number:0604

Physical & Chemical Properties

Phase:Gas
Density:3.749 g/L
Boiling Point:119.93 K ​(−153.415 °C, ​−244.147 °F)
Melting Point:115.78 K ​(−157.37 °C, ​−251.27 °F)
Molecular Formula:Kr
Flash Point:n/a
Exact Mass:83.91150
Symbol:Globally Harmonized System of Classification
Signal Word:Warning
Hazard Statements:H280
Precautionary Statements:n/a
Hazard Codes:n/a
Risk Phrases:R9
Safety Phrases:9-38
RIDADR:UN 1950 2
WGK Germany:3
RTECS:n/a
Packaging Group:n/a
Hazard Class:2.2

Krypton isotopes are used in various medical and scientific applications. Kr-82 is used for the production of Rb-81/Kr-81m generators.
Many of the stable isotopes of Krypton are used in the study of the pulmonary system. Kr-78 can be used for the production of Br-75 although production of Br-75 via Se-76 is more common. Kr-86 has been used to define the standard measure of length: 1 meter is exactly 1,650,763.73 wavelengths of this isotope.

Naturally occurring isotopes

IsotopeMass/DaNatural abundance (atom %)Nuclear spin (I)Magnetic moment (μ/μN)
78Kr77.920396 (9)0.35 (1)0
80Kr79.916380 (9)2.28 (6)0
82Kr81.913482 (6)11.58 (14)0
83Kr82.914135 (4)11.49 (6)9/2-0.970669
84Kr83.911507 (4)57.00 (4)0
86Kr85.910616 (5)17.30 (22)0

Radiosotope data

IsotopeMass/DaHalf-lifeMode of decayNuclear spinNuclear magnetic moment
74Kr73.933311.5 mEC to 74Br0
75Kr74.931044.3 mEC to 75Br
76Kr75.9259514.8 hEC to 76Br0
77Kr76.924671.24 hEC to 77Br5/2
79Kr78.9200831.455 dEC to 79Br1/2
81Kr80.916593210000 yEC to 81Br7/2
85Kr84.91253010.73 yβ to 85Rb9/21.005
87Kr86.9133591.27 hβ to 87Rb5/2-1.018
88Kr87.914452.84 hβ to 88Rb0
89Kr88.917643.15 mβ to 89Rb5/2

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