01 n. An inert gaseous element of the argon (noble gas) group, of atomic number 36, occurring in air to the extent of about one volume in a milli…
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An inert gaseous element of the argon (noble gas) group, of atomic number 36, occurring in air to the extent of about one volume in a million. It was discovered by Ramsay and Travers in 1898. Boiling point, -152.3° C.; melting point, -156.6° C.; symbol, Kr; atomic weight, 83.8.(Chem.)