Electronic data		Thermal data		Steric data
Shells: 2,8,18,8 Orbitals: [Ar] 3d10 4s2 4p6 Electronegativity: 2.7, -- 1. Ionization potential: 13.9996 eV 2. Ionization potential: 24.359 eV 3. Ionization potential: 36.95 eV Oxidation states: 2 Electrical conductivity: --		Melting point: -156.6 °C Boiling point: -152.3 °C Specific heat: 0.248 J/gK Heat of fusion: 1.638 kJ/mol Heat of vaporization: 9.029 kJ/mol Thermal conductivity: 0.0000949 W/cmK		Atomic radius: 1.03 Å Ionic radius: -- Å () Covalent radius: 1.12 Å Atomic volume: 38.9 cm³/mol Density (293 K): 0.003708 g/cm³ Crystal structure: Cubic: Face centered

Nuclide	Abundance [%]	Mass	Spin	Halflife	Decay mode	Decay tree
78Kr	0.35	77.9204	0	--	stable	--
79Kr	0	79	1/2	1.45d	EC,+	View
80Kr	2.27	79.9164	0	--	stable	--
81Kr	0	80.917	7/2	2.1E05y	EC	View
82Kr	11.56	81.9135	0	--	stable	--
83Kr	11.55	82.9141	9/2	--	stable	--
83Krm	0	83	1/2	1.86h	IT	View
84Kr	56.9	83.9115	0	--	stable	--
85Kr	0	84.913	9/2	10.73y	-	View
85Krm	0	85	1/2	4.48h	-,IT	View
86Kr	17.37	85.9106	0	--	stable	--
87Kr	0	87	5/2	1.27h	-	View
88Kr	0	88	0	2.84h	-	View
89Kr	0	89	0	3.15m	-	View
90Kr	0	90	0	32.3s	-,b-	View

Legend

Name origin:	Greek: kryptos (hidden)
Description:	Colorless, odorless, tasteless rare noble gas.
Discovered by:	Sir William Ramsey, M.W. Travers
Year:	1898
Place:	Great Britain
Sources:	Forms 1 millionth of the atmosphere. Obtained from production of liquid air.
Use(s):	Used in lighting products. Some is used as inert filler-gas in incandescent bulbs. Some is mixed with argon in fluorescent lamps. The most important use is in flashing stroboscopic lamps that outline airport runways.