| Property | Radon | Reference |
|---|---|---|
| Molecular weight | 222 (radon), 220 (thoron), 219 (actinon) | Cothern 1987a |
| Color | Colorless | Lewis 2001 |
| Physical state | Gas at 0 °C and 760 mm Hg | Lewis 2001 |
| Melting point | −71 °C | Lide 2005 |
| Boiling point | −61.8 °C | Lewis 2001 |
| Density at −20 °C | 9.96×10−3 g/cm3 | Cothern 1987a |
| Odorb | Odorless | O’Neil et al. 2006 |
| Odor threshold: | ||
| Water | Odorless | |
| Air | Odorless | |
| Solubility: | ||
| Water at 20 °C | 230 cm3/L | O’Neil et al. 2006 |
| Organic solvents | Organic liquid, slightly soluble in alcohol | Weast 1980 |
| Vapor pressure at 25 °Ca | 395.2 mm Hg | Cothern 1987a |
| Henry’s Law constant | No data | |
| Autoignition temperature | Noble gas; does not autoignite | |
| Flash point | Noble gas; does not burn | |
| Flammability limits | Noble gas; is not flammable | |
| Half-life: | ||
| 222Rn | 3.8235 days | DOE 2008 |
| 220Rn | 55.6 seconds | DOE 2008 |
| 219Rn | 3.96 seconds | DOE 2008 |
| Decay energies (MeV), and intensities (%) | ||
| 222Rn | Alpha particles: | DOE 2008 |
| 4.826 (0.0005%) | ||
| 4.986 (0.078%) | ||
| 5.48948 (99.920%) | ||
| Gamma rays: | ||
| 0.510 (0.076%) | ||
| 220Rn | Alpha particles: | DOE 2008 |
| 5.747 (0.114%) | ||
| 6.288 (99.886%) | ||
| Gamma rays: | ||
| 0.5497 (0.114%) | ||
| 219Rn | Alpha particles (15 reported): | U.S. DHEW 1970 |
| 6.425 (7.5%) | ||
| 6.530 (0.12%) | ||
| 6.553 (12.9%) | ||
| 6.819 (79.4%) | ||
| Gamma rays (dozens reported): | ||
| 0.0111 (9.6% | ||
| 0.0769 (5.0%) | ||
| 0.0793 (8.4%) | ||
| 0.2712 (10.8%) | ||
| Specific activity, nλ/mass (Ci/g): | ||
| 222Rn | 1.538×105 | Based on DOE 2008 |
| 220Rn | 9.135×108 | Based on DOE 2008 |
| 219Rn | 1.301×1010 | Based on DOE 2008 |
| Decay products: | Radon progeny (daughters) | |
| 222Rn (see Figure 4-1) | 218Po | DOE 2008 |
| 214Pb | ||
| 214Bi | ||
| 214Po | ||
| 210Tl | ||
| 210Pb | ||
| 210Bi | ||
| 210Po | ||
| 206Tl | ||
| 206Pb | ||
| 220Rn (see Figure 4-2) | 216Po | DOE 2008 |
| 212Pb | ||
| 212Bi | ||
| 212Po | ||
| 208Tl | ||
| 208Pb | ||
| 219Rn (see Figure 4-3) | 215Po | DOE 2008 |
| 215At | ||
| 211Pb | ||
| 211Bi | ||
| 211Po | ||
| 207Tl | ||
| 207Pb | ||
MeV = million electron volts
From: 4, CHEMICAL, PHYSICAL, AND RADIOLOGICAL INFORMATION
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