Radon, radioactive

CAS RN: 10043-92-2

Other Properties

Noble gas
The heaviest gas known.
Valence: usually zero. Specific gravity liquid: 4.4 at -62 deg C; solid: 4.4
Heat of fusion: 3247 J/mol
Henry's Law constant: 9.3X10-3 mol/kg-bar at 298.1 K
... Radon is a member of a class of gases known as rare, inert, or noble gases. This class includes helium, neon, argon, krypton, xenon. ... isotopes of radon, all having short half-lives, are formed by the radioactive decay of radium, actinium, and thorium.
The radioactive noble gas radon is produced by decay of the naturally occurring radionuclide, radium-226, which in turn is a decay product of uranium-238. Since radon is a gas, it may escape into the air from the material in which it is formed, and since uranium and radium occur widely in soil, rocks and water, radon gas is ubiquitous. ... Radon decays to a number of short lived progeny that are radioactive. These may attach to available aerosol particle in the atmosphere, thereby forming attached radon progeny whose size will reflect the size distribution of the ambient aerosol. Radon progeny that do not attach to aerosols remain in the unattached state, and these unattached particles are usually found to be in the approximate size range of 0.5 to 5 nm.
There are 37 isotopes and isomers of radon
Naturally occurring isotopes are radon-219, radon-220, and radon-222. Radon-195 through -218, radon-221, and radon-223 through -228 are artificially produced and are radioactive.
Atomic weight: 219.009480; half-life: 3.96 seconds; alpha emission, 6.946 MeV /Radon-219/
Atomic weight: 220.011394; half-life: 55.6 seconds; alpha emission, 6.404 MeV /Radon-220/
Atomic weight: 222.017578; half-life: 3.823 days; alpha emission, 5.590 MeV /Radon-222/
Radon-219 Decay Pathway
Parent Half-life Pathway Daughter
Radon-219, naturally occurring isotope 3.96 seconds alpha emission (6946 keV) polonium-215
Polonium-215 1.781 milli-seconds alpha emission (7526 keV) lead-211
Lead-211 36.1 minutes beta emission (1373 keV) bismuth-211
Bismuth-211 2.14 minutes alpha emission (99.72%, 6751 keV) thallium-207
beta emission (0.28 %, 0579 keV) polonium-211
Thallium-207 4.77 minutes beta(-) emission (1427 keV) lead-207
Polonium-211 0.516 seconds alpha emission (7594.1 keV) lead-207
Lead-207 stable
Radon-222 Decay Pathway
Parent Half-life Pathway Daughter
Radon-220, naturally occurring isotope 55.6 seconds alpha emission (6405 keV) polonium-216
Polonium-216 0.145 seconds alpha emission (6906 keV) lead-212
Lead-212 10.64 hours beta emission (570 keV) bismuth-212
Bismuth-212 60.55 minutes beta emission (60.06%, 2254 keV) polonium-212
alpha emission (35.94%, 6207 keV) thallium-208
Polonium-212 0.299 micro-seconds alpha emission (8594.13 keV) lead-208
Thallium-208 3.053 minutes beta(-) emission (4994 keV) lead-208
Lead-208 stable
Radon-222 Decay Pathway
Parent Half-life Pathway Daughter
Radon-222, naturally occurring isotope 3.8235 days alpha emission (5590.3 keV) polonium-218
Polonium-218 3.10 minutes alpha emission (6114.68 keV) lead-214
Lead-214 26.8 minutes beta(-) emission (1023 keV) bismuth-214
Bismuth-214 19.9 minutes alpha emission (0.021%) (6751.1 keV) thallium-210
decays via beta(-) emission (99.979%) (3272 keV) polonium-214
Thallium-210 1.20 minutes beta(-) emission (5490 keV) lead-210
Polonium-214 164.3 microseconds alpha emission (7833.46keV) lead-210
Lead-210 22.2 yrs beta(-) emission (63.5 keV) bismuth 210
Bismuth-210 5.012 days beta(-) emission (1162.1 keV) polonium-210
Polonium-210 138.376 days alpha emission (5407.70 keV) lead-206
Lead-206 stable
Synthetic radon isotope decay data.
Isotope Energy (MeV) Half-life
Rn-193 9.0429 1.15 milli-seconds
Rn-194 5.7234 0.78 milli-seconds
Rn-195 5.1092 6 milli-seconds
Rn-196 1.9709 4.4 milli-seconds
Rn-197 1.5103 54 milli-seconds
Rn-198 -1.2303 65 milli-seconds
Rn-199 -1.4994 0.59 seconds
Rn-200 -4.0047 1.03 seconds
Rn-201; Rn-201m -4.0723; -4.0723 7.0; 3.8 seconds
Rn-202 -6.2746 9.7 seconds
Rn-203; Rn-203m -6.1536; -5.7916 44; 26.9 seconds
Rn-204 -7.9701 74.5 seconds
Rn-205 -7.7097 170 seconds
Rn-206 -9.1329 5.67 minutes
Rn-207 -8.6347 9.25 minutes
Rn-208 -9.6555 24.35 minutes
Rn-209 -8.9410 28.8 minutes
Rn-210 -9.6047 2.4 hrs
Rn-211 -8.7554 14.6 hrs
Rn-212 -8.6596 23.9 minutes
Rn-213 -5.6960 19.5 milli-seconds
Rn-214 -4.3197 0.27 micro-seconds
Rn-215 -1.1685 2.30 micro-seconds
Rn-216 0.2528 45 micro-seconds
Rn-217 3.6585 0.54 milli-seconds
Rn-218 5.2173 35 milli-seconds
Rn-221 14.4714 25 minutes
Rn-223 20.3897 24.3 minutes
Rn-224 22.4450 107 minutes
Rn-225 26.5341 4.66 minutes
Rn-226 28.7471 7.4 minutes
Rn-227 32.8858 20.2 seconds
Rn-228 35.2434 65 seconds
Rn-229 39.3624 12.0 seconds
Rn-230 42.0480 >300 nano-seconds
Rn-231 46.4540 >300 nano-seconds
Find more information on this substance at: PubChem, PubMed