a radioactive gaseous element formed by the disintegration of radium; the heaviest of the inert gasses; occurs naturally (especially in areas over granite) and is considered a hazard to health
[ Syn: rn , rn , atomic number 86 , atomic number 86 ]
a radioactive gaseous element formed by the disintegration of radium; the heaviest of the inert gasses; occurs naturally (especially in areas over granite) and is considered a hazard to health
[ Syn: rn , rn , atomic number 86 , atomic number 86 ]