| krypton | <chemical> A noble gas that is found in the atmosphere. It has the atomic symbol kr, atomic number 36, atomic weight 83.80, and has been used in electric bulbs. Chemical name: Krypton (12 Dec 1998) |
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| krypton radioisotopes | Unstable isotopes of krypton that decay or disintegrate emitting radiation. Kr atoms with atomic weights 74-77, 79, 81, 85, and 87-94 are radioactive krypton isotopes. (12 Dec 1998) |