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krypton-85

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Also known as Kr-85, 85Kr, krypton kr-85

Krypton-85 (85Kr) is a radioisotope of krypton, distributed throughout the atmosphere and presently forming about 15 ppt of atmospheric krypton on average.

Key facts

Isotope.symbol
Kr
Isotope.mass_number
85
Isotope.mass
84.9125273(21)
Isotope.num_neutrons
49
Isotope.num_protons
36
Isotope.decay_product
Rubidium
Isotope.decay_symbol
Rb
Isotope.decay_mass
85
Isotope.decay_mode1
Beta decay
Isotope.decay_energy1
0.687
Isotope.decay_mode2
Beta decay
Isotope.decay_energy2
0.173
Isotope.spin
9/2+
Isotope.excess_energy
−81480.267
Isotope.binding_energy
8698.562

via Wikipedia infobox

Wikidata facts

Mass
84.913
Show 10 more facts
atomic number
36
neutron number
49
half-life
10.752
spin quantum number
4.5
parity quantum number
1
mass excess
-81480.331
binding energy
739377.77
canonical SMILES
[Kr]
chemical formula
Kr
isomeric SMILES
[85Kr]
Sources (6)

via Wikidata · CC0

~5 min read

Article

5 sections
Contents
  • Presence in Earth's atmosphere
  • Natural production
  • Anthropogenic production
  • Uses in industry
  • References

Krypton-85 (85Kr) is a radioisotope of krypton, distributed throughout the atmosphere and presently forming about 15 ppt of atmospheric krypton on average.

Krypton-85 has a half-life of 10.728 years and a maximum decay energy of 687 keV. It decays into stable rubidium-85. Its most common decay (99.57%) is by beta particle emission with a maximum energy of 687 keV and an average energy of 251 keV. The second most common decay (0.43%) is by beta particle emission (maximum energy of 173 keV) followed by gamma ray emission (energy of 514 keV). Other decay modes have very small probabilities and emit less energetic gamma rays. Krypton-85 is mostly synthetic, though it is produced naturally in trace quantities by cosmic ray spallation.

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