Noble gas (data page)

This page provides supplementary data about the noble gases, which had to be excluded from the main article for reasons of space and focus.

Physical properties

Solid

Physical property	Helium	Neon	Argon	Krypton	Xenon	Radon
Density, solid at tp (g/dm³)[1]	–	1444	1623	2826	3540	–
Crystal structure[2]	hcp	fcc	fcc	fcc	fcc	fcc

Liquid

Physical property	Helium	Neon	Argon	Krypton	Xenon	Radon
Density, liquid at bp and 1 atm (g/dm³)[1]	125.0	1207	1393.9	2415	3057	4400
Density, liquid at tp (g/dm³)[1]	–	1247	1415	2451	3084	–
Thermal conductivity, liquid at bp (mW m−1 K−1)[1]	31.4	129.7	121.3	88.3	73.2	–
Dielectric constant (liquid)[3]	1.055[4]	1.53[5]	–	–	–	–

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
Dynamic Viscosity (kPa·s)[2]	186	297	210	233	211	–
Thermal conductivity at 0 °C (J s−1 m−1 K−1)[6]	0.1418	0.0461	0.0169	0.00874	0.00506	–
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) [6]	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	–
Molar refraction (D line, cm3)[7]	0.521	1.004	4.203	6.397	10.435	–
Dielectric constant (gas)[3]	1.0000684[8]	1.000545[9]	1.000127	–	–	–
van der Waals constant a (L2bar/mol2)[3]	0.03412	0.2107	1.345	2.318	4.194	–
van der Waals constant b (L/mol)[3]	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
Melting point (°C)[2]	−	−248.5	−189.6	−157.4	−111.5	−71.0
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[10]	24.562	83.80	115.76	161.37	202
Triple point pressure (kPa)[1]	5.1[10]	43.37	68.90	73.15	81.66	70

Atomic properties

Atomic property	Helium	Neon	Argon	Krypton	Xenon	Radon
Atomic number[6]	2	10	18	36	54	86
Relative atomic mass[6]	4.002602(2)	20.1797(6)	39.948(1)	83.80(1)	131.29(2)	(222)
Number of natural isotopes[6]	2	3	3	6	9	(1)
Outer shell electron configuration[6]	1s2	2s22p6	3s23p6	4s24p6	5s25p6	6s26p6
Atomic radius (pm)[2]	130	160	192	198	218	–
Ionization energy (kJ/mol)[6]	2372	2080	1520	1351	1170	1037
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	–

Abundance

Abundance	Helium	Neon	Argon	Krypton	Xenon	Radon
Solar System (for each atom of silicon)[11]	2343	2.148	0.1025	5.515 × 10−5	5.391 × 10−6	–
Earth's atmosphere (volume fraction in ppm)[12]	5.20	18.20	9340.00	1.10	0.09	trace
Igneous rock (mass fraction in ppm)[6]	3 × 10−3	7 × 10−5	4 × 10−2	–	–	1.7 × 10−10

Economic data

Gas	2004 price (USD/m3)[1]
Helium (industrial grade)	4.20–4.90
Helium (laboratory grade)	22.30–44.90
Argon	2.70–8.50
Neon	60–120
Krypton	400–500
Xenon	4000–5000
Radon	?

References and notes

1. ^ ^{a b c d e f g h i j} Shuen-Chen Hwang, Robert D. Lein, Daniel A. Morgan (2005). "Noble Gases". Kirk Othmer Encyclopedia of Chemical Technology. Wiley. pp. 343–383. doi:10.1002/0471238961.0701190508230114.a01. 
2. ^ ^{a b c d e f g h i j k l} "Noble Gas". Encyclopædia Britannica. 2008. http://www.britannica.com/eb/article-9110613/noble-gas. 
3. ^ ^{a b c d} Lide, D. R. (Ed.) (1990). CRC Handbook of Chemistry and Physics (70th Edn.). Boca Raton (FL):CRC Press. 
4. ^ at 2.06–2.63 K
5. ^ at −191 °C
6. ^ ^{a b c d e f g h} Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Oxford: Butterworth-Heinemann. ISBN 0080379419. 
7. ^ Peter Häussinger, Reinhard Glatthaar, Wilhelm Rhode, Helmut Kick, Christian Benkmann, Josef Weber, Hans-Jörg Wunschel, Viktor Stenke, Edith Leicht, Hermann Stenger (2002). "Noble gases". Ullmann's Encyclopedia of Industrial Chemistry. Wiley. doi:10.1002/14356007.a17_485. 
8. ^ <3 × 10⁶ Hz at 140 °C
9. ^ 10¹⁰ Hz at 23 °C
10. ^ ^{a b} Lambda point for pure ⁴He from Yunus A. Cengel, Robert H. Turner. Fundamentals of thermal-fluid sciences. McGraw-Hill, 2004, p. 78. ISBN 0072976756
11. ^ Katharina Lodders (2003). "Solar System Abundances and Condensation Temperatures of the Elements". The Astrophysical Journal 591 (2): 1220–1247. Bibcode 2003ApJ...591.1220L. doi:10.1086/375492. 
12. ^ "The Atmosphere". National Weather Service. http://www.srh.noaa.gov/jetstream//atmos/atmos_intro.htm. Retrieved 2008-06-01.