Noble gas (data page)
Supplementary information on noble gases
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This page provides supplementary data about the noble gases, which were excluded from the main article to conserve space and preserve focus. Oganesson is mostly not included due to the limited amount of known data.
Physical properties
Solid
Liquid
| Physical property | Helium | Neon | Argon | Krypton | Xenon | Radon |
|---|---|---|---|---|---|---|
| Density, liquid at boiling point and 1 atm (g/dm³)[1] | 125.0 | 1207 | 1393.9 | 2415 | 3057 | 4400 |
| Density, liquid at triple point (g/dm³)[1] | – | 1247 | 1415 | 2451 | 3084 | – |
| Thermal conductivity, liquid at boiling point (mW m−1 K−1)[1] | 31.4 | 129.7 | 121.3 | 88.3 | 73.2 | – |
| Dielectric constant (liquid)[3][4] | 1.057[5][6] | 1.191[7][8] | 1.325 [9] | 1.664[10] | 1.880[11] | — |
Gas
| Physical property | Helium | Neon | Argon | Krypton | Xenon | Radon |
|---|---|---|---|---|---|---|
| Density, gas at 0 °C and 1 atm (g/dm³)[2] | 0.1786 | 0.9002 | 1.7818 | 3.708 | 5.851 | 9.97 |
| Thermal conductivity at 0 °C (J s−1 m−1 K−1)[12] | 0.1418 | 0.0461 | 0.0169 | 0.00874 | 0.00506 | 0.0036[13] |
| Mean free path at STP (nm)[2] | 192.66 | 135.36 | 68.33 | 52.34 | 37.88 | – |
| Solubility in water at 20 °C (cm3/kg) [12] | 8.61 | 10.5 | 33.6 | 59.4 | 108.1 | 230 |
| Magnetic susceptibility (cgs units per mole)[2] | −0.0000019 | −0.0000072 | −0.0000194 | −0.000028 | −0.000043 | – |
| Heat capacity, Cp, gas at 1 atm (J mol−1 K−1)[1] | 20.78 | 20.79 | 20.85 | 20.95 | 21.01 | 21 |
| Sonic velocity at 0 °C and 1 atm (m/s)[1] | 973 | 433 | 307.8 | 213 | 168 | – |
| Thermal conductivity, gas at 0 °C and 1 atm (mW m−1 K−1)[1] | 141.84 | 46.07 | 16.94 | 8.74 | 5.06 | 3.6[13] |
| Molar refraction (D line, cm3)[14] | 0.521 | 1.004 | 4.203 | 6.397 | 10.435 | – |
| Dielectric constant (gas)[15] | 1.0000684[16] | 1.00013[17] | 1.000516[18] | – | – | – |
| van der Waals constant a (L2bar/mol2)[15] | 0.03412 | 0.2107 | 1.345 | 2.318 | 4.194 | – |
| van der Waals constant b (L/mol)[15] | 0.02370 | 0.01709 | 0.03219 | 0.03978 | 0.05105 | – |
Phase changes and critical properties
| Physical property | Helium | Neon | Argon | Krypton | Xenon | Radon |
|---|---|---|---|---|---|---|
| Boiling point (°C)[2] | −268.8 | −245.9 | −185.8 | −151.7 | −106.6 | −61.7 |
| Boiling point (K) | 4.15 | 27.15 | 87.15 | 121.2 | 165.2 | 211.3 |
| Melting point (°C)[2] | −272 | −248.5 | −189.6 | −157.4 | −111.5 | −71.0 |
| Melting point (K) | 1.15 | 24.65 | 83.55 | 115.75 | 161.65 | 202.15 |
| Critical temperature (K)[2] | 5.25 | 44.5 | 150.85 | 209.35 | 289.74 | 378.15 |
| Critical pressure (atm)[2] | 2.26 | 26.9 | 48.3 | 54.3 | 57.64 | 62 |
| Critical density (g/mL)[2] | 0.0693 | 0.484 | 0.536 | 0.908 | 1.100 | – |
| Triple point temperature (K)[1] | 2.19[19] | 24.562 | 83.80 | 115.76 | 161.37 | 202 |
| Triple point pressure (kPa)[1] | 5.1[19] | 43.37 | 68.90 | 73.15 | 81.66 | 70 |
Atomic properties
| Atomic property | Helium | Neon | Argon | Krypton | Xenon | Radon | Oganesson |
|---|---|---|---|---|---|---|---|
| Atomic number[12] | 2 | 10 | 18 | 36 | 54 | 86 | 118 |
| Standard atomic weight[12] | 4.002602(2) | 20.1797(6) | 39.948(1) | 83.80(1) | 131.29(2) | (222) | (294) |
| Number of natural isotopes[12] | 2 | 3 | 3 | 6 | 9 | 4 | 0 |
| Outer shell electron configuration[12] | 1s2 | 2s22p6 | 3s23p6 | 4s24p6 | 5s25p6 | 6s26p6 | 7s27p6 |
| Atomic radius (pm)[2] | 31 | 38 | 71 | 88 | 108 | 120 | 138 |
| Ionization energy (kJ/mol)[12] | 2372 | 2080 | 1520 | 1351 | 1170 | 1037 | 839 |
| Static polarizability[2] (Å3) | 0.204 | 0.392 | 1.63 | 2.465 | 4.01 | – | – |
| Average Valence Electron Energy (AVEE) | 4.16 | 4.79 | 3.24 | 2.97 | 2.58 | 2.60 | – |
Abundance
| Abundance | Helium | Neon | Argon | Krypton | Xenon | Radon | Oganesson |
|---|---|---|---|---|---|---|---|
| Solar System (for each atom of silicon)[20] | 2343 | 2.148 | 0.1025 | 5.515 × 10−5 | 5.391 × 10−6 | – | – |
| Earth's atmosphere (volume fraction in ppm)[21] | 5.20 | 18.20 | 9340.00 | 1.10 | 0.09 | (0.06–18) × 10−19 | 0 |
| Igneous rock (mass fraction in ppm)[12] | 3 × 10−3 | 7 × 10−5 | 4 × 10−2 | – | – | 1.7 × 10−10 | 0 |
Economic data
Radon is available only in very small quantities, and due to its short half-life, is generally produced by a radium-226 source in secular equilibrium.[22] Oganesson is almost impossible to produce and with a very short half-life, it is not readily available for purchase.