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
Physical property Helium Neon Argon Krypton Xenon Radon Density, solid at triple point (g/dm³) – 1444 1623 2826 3540 – Crystal structure hcp fcc fcc fcc fcc fcc
Liquid
Physical property Helium Neon Argon Krypton Xenon Radon Density, liquid at boiling point and 1 atm (g/dm³) 125.0 1207 1393.9 2415 3057 4400 Density, liquid at triple point (g/dm³) – 1247 1415 2451 3084 – Thermal conductivity, liquid at boiling point (mW m−1 K−1) 31.4 129.7 121.3 88.3 73.2 – Dielectric constant (liquid) 1.057at 1.5–2.5 K 1.191at 26.11 K 1.325 at 140 K 1.664at 119.80K 1.880at 161K —
Gas
Physical property Helium Neon Argon Krypton Xenon Radon Density, gas at 0 °C and 1 atm (g/dm³) 0.1786 0.9002 1.7818 3.708 5.851 9.97 Thermal conductivity at 0 °C (J s−1 m−1 K−1) 0.1418 0.0461 0.0169 0.00874 0.00506 0.0036Generalic, Eni,"Radon," EniG. Periodic Table of the Elements. 27 May 2013. KTF-Split. (accessed 30 May 2013). Mean free path at STP (nm) 192.66 135.36 68.33 52.34 37.88 – Solubility in water at 20 °C (cm3/kg) 8.61 10.5 33.6 59.4 108.1 230 Magnetic susceptibility (cgs units per mole) −0.0000019 −0.0000072 −0.0000194 −0.000028 −0.000043 – Heat capacity, Cp, gas at 1 atm (J mol−1 K−1) 20.78 20.79 20.85 20.95 21.01 21 Sonic velocity at 0 °C and 1 atm (m/s) 973 433 307.8 213 168 – Thermal conductivity, gas at 0 °C and 1 atm (mW m−1 K−1) 141.84 46.07 16.94 8.74 5.06 3.6 Molar refraction (D line, cm3) 0.521 1.004 4.203 6.397 10.435 – Dielectric constant (gas) 1.0000684<3 × 106 Hz at 140 °C 1.00013106 Hz at 0°C 1.0005161015 Hz at 20°C – – – van der Waals constant a (L2bar/mol2) 0.03412 0.2107 1.345 2.318 4.194 – van der Waals constant b (L/mol) 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) −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) −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) 5.25 44.5 150.85 209.35 289.74 378.15 Critical pressure (atm) 2.26 26.9 48.3 54.3 57.64 62 Critical density (g/mL) 0.0693 0.484 0.536 0.908 1.100 – Triple point temperature (K) 2.19Lambda point for pure 4He from Yunus A. Cengel, Robert H. Turner. Fundamentals of thermal-fluid sciences. McGraw-Hill, 2004, p. 78. 24.562 83.80 115.76 161.37 202 Triple point pressure (kPa) 5.1 43.37 68.90 73.15 81.66 70
Atomic properties Atomic property Helium Neon Argon Krypton Xenon Radon Oganesson Atomic number 2 10 18 36 54 86 118 Standard atomic weight 4.002602(2) 20.1797(6) 39.948(1) 83.80(1) 131.29(2) (222) (294) Number of natural isotopes 2 3 3 6 9 4 0 Outer shell electron configuration 1s2 2s22p6 3s23p6 4s24p6 5s25p6 6s26p6 7s27p6 Atomic radius (pm) 31 38 71 88 108 120 138 Ionization energy (kJ/mol) 2372 2080 1520 1351 1170 1037 839 Static polarizability (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) 2343 2.148 0.1025 5.515 × 10−5 5.391 × 10−6 – – Earth's atmosphere (volume fraction in ppm) 5.20 18.20 9340.00 1.10 0.09 (0.06–18) × 10−19 0 Igneous rock (mass fraction in ppm) 3 × 10−3 7 × 10−5 4 × 10−2 – – 1.7 × 10−10 0
Economic data Gas 2004 price (USD/m3) Helium (industrial grade) 4.20–4.90 Helium (laboratory grade) 22.300–44.90 Argon 2.70–8.50 Neon 60–120 Krypton 400–500 Xenon 4000–5000 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. Oganesson is almost impossible to produce and with a very short half-life, it is not readily available for purchase.
References and notes