Template:Infobox krypton

Krypton,  ₃₆Kr

A krypton-filled discharge tube glowing white
Spectral lines of krypton
General properties
Name, symbol	krypton, Kr
Appearance	colorless gas, exhibiting a whitish glow in a high electric field
Pronunciation	/ˈkrɪptɒn/ KRIP-ton
Krypton in the periodic table
Ar ↑ Kr ↓ Xe bromine ← krypton → rubidium
Atomic number (Z)	36
Group, block	group 18 (noble gases), p-block
Period	period 4
Element category	noble gas
Standard atomic weight (±) (Ar)	83.798(2)
Electron configuration	[Ar] 3d10 4s2 4p6
per shell	2, 8, 18, 8
Physical properties
Phase	gas
Melting point	115.78 K ​(−157.37 °C, ​−251.27 °F)
Boiling point	119.93 K ​(−153.415 °C, ​−244.147 °F)
Density at stp (0 °C and 101.325 kPa)	3.749 g/L
when liquid, at b.p.	2.413 g/cm3
Triple point	115.775 K, ​73.53 kPa
Critical point	209.48 K, 5.525 MPa
Heat of fusion	1.64 kJ/mol
Heat of vaporization	9.08 kJ/mol
Molar heat capacity	20.95 J/(mol·K)
vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 59 65 74 84 99 120
Atomic properties
Oxidation states	2, 1, 0 ​(rarely more than 0; unknown oxide)
Electronegativity	Pauling scale: 3.00
Ionization energies	1st: 1350.8 kJ/mol 2nd: 2350.4 kJ/mol 3rd: 3565 kJ/mol
Covalent radius	116±4 pm
Van der Waals radius	202 pm
Miscellanea
Crystal structure	​face-centered cubic (fcc)
Speed of sound	(gas, 23 °C) 220 m·s−1 (liquid) 1120 m/s
Thermal conductivity	9.43×10−3  W/(m·K)
Magnetic ordering	diamagnetic
CAS Number	7439-90-9
History
Discovery and first isolation	William Ramsay and Morris Travers (1898)
Most stable isotopes of krypton
iso NA half-life DM DE (MeV) DP 78Kr 0.35% >1.1×1020 y (β+β+) 2.846 78Se 79Kr syn 35.04 h ε – 79Br β+ 0.604 79Br γ 0.26, 0.39, 0.60 – 80Kr 2.25% 80Kr is stable with 44 neutrons 81Kr trace 2.29×105 y ε – 81Br γ 0.281 – 82Kr 11.6% 82Kr is stable with 46 neutrons 83Kr 11.5% 83Kr is stable with 47 neutrons 84Kr 57.0% 84Kr is stable with 48 neutrons 85Kr syn 10.756 y β− 0.687 85Rb 86Kr 17.3% – (β−β−) 1.2556 86Sr
Decay modes in parentheses are predicted, but have not yet been observed

References

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