a. A heavy, radioactive, gaseous element; inert; the heaviest known gas.
Symbol, Rn. Formed by the disintegration of uranium. Used similarly to
radium in medicine. Radon build-up is a health consideration in uranium
mines. Handbook of Chemistry and Physics, 3
b. Heaviest known gas. Colorless as a gas; yellow to orange-red,
phosphorescent, opaque crystals; sp gr of liquid, 4.4 (at -62 degrees C);
and of solid, 4.0; soluble in water; and slightly soluble in alcohol and
in organic liquids. All 18 known isotopes from radon-204 to radon-224 are
radioactive. Radon-222 emanates from thorium; half-life, 54.5 s; and an
alpha particle emitter; and radon-219 or actinon emanates from actinium;
half-life, 3.92 s; and an alpha particle and a gamma ray emitter. One part
of radon exists in 1 sextillion parts of air.
Handbook of Chemistry and Physics, 2
Dictionary of Mining, Mineral, and Related Terms