Krypton

Krypton (Kr)

Colorless gaseous element, belongs to the noble gases. Occurs in the air, 0.0001% by volume. It can be extracted from liquid air by fractional distillation. Generally not isolated, but used with other inert gases in fluorescent lamps. Five natural isotopes, and five radioactive isotopes. Kr-85, the most stable radioactive isotope, has a half-life of 10.76 years and is produced in fission reactors. Practically inert, though known to form compounds with Fluorine.
Atomic Number36
Atomic Weight83.798
Mass Number84
Group18
Period4
Blockp
Protons36 p+
Neutrons48 n0
Electrons36 e-
Krypton discharge tube.jpg Animated Bohr Model of Kr (Krypton) Enhanced Bohr Model of Kr (Krypton) Bohr Model: Kr (Krypton) Orbital Diagram of Kr (Krypton)

Properties

Atomic Radius
Molar Volume
Covalent Radius
117 pm
Metallic Radius
Ionic Radius
Crystal Radius
Van der Waals Radius
202 pm
Density
0.003425 g/cm³
Energy
Proton Affinity
424.6 kJ/mol
Electron Affinity
Ionization Energy
13.9996049 eV/particle
Heat of Vaporization
9.05 kJ/mol
Heat of Fusion
Heat of Formation
Electrons
Electron Shells2, 8, 18, 8
Valence Electrons2
Electron Configuration[Ar] 3d10 4s2 4p6
Oxidation States0, 1, 2
Electronegativity
Electrophilicity
Phases
PhaseGas
Gas PhaseMonoatomic
Boiling Point
119.735 K
Melting Point
115.78 K
Critical Pressure
5.525 MPa
Critical Temperature
209.48 K
Triple Point
115.775 K
73.53 kPa
Visual
Color
Colorless
Appearancecolorless gas, exhibiting a whitish glow in a high electric field
Refractive Index
1.000427
Thermodynamic Properties
Thermal Conductivity
0.0095 W/(m K)
Thermal Expansion
Molar Heat Capacity
20.786 J/(mol K)
Specific Heat Capacity
0.248 J/(g⋅K)
Heat Capacity Ratio (Adiabatic Index)5/3
Electrical Properties
Type
Electrical Conductivity
Electrical Resistivity
Superconducting Point
Magnetism
Typediamagnetic
Magnetic Susceptibility (Mass)
-0.0000000044 m³/Kg
Magnetic Susceptibility (Molar)
-0.000000000369 m³/mol
Magnetic Susceptibility (Volume)
-0.0000000165
Magnetic Ordering
Curie Point
Neel Point
Structure
Crystal StructureFace Centered Cubic (FCC)
Lattice Constant
5.72 Å
Lattice Anglesπ/2, π/2, π/2
Mechanical Properties
Hardness
Bulk Modulus
Shear Modulus
Young Modulus
Poisson Ratio
Speed of Sound
1,120 m/s
Classification
CategoryNoble gases, Noble gases
CAS GroupVIII
IUPAC GroupVIIIA
Glawe Number4
Mendeleev Number115
Pettifor Number4
Geochemical Classvolatile
Goldschmidt Classatmophile
Other
Gas Basicity
402.4 kJ/mol
Dipole Polarizability
16.78 ± 0.02 a₀
C6 Dispersion Coefficient
130 a₀
Allotropes
Neutron Cross Section
25
Neutron Mass Absorption
0.013
Quantum Numbers1S0
Space Group225 (Fm_3m)

Isotopes of Krypton

Stable Isotopes6
Unstable Isotopes29
Radioactive Isotopes29

67Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
66.983305 ± 0.000455 Da
Mass Number67
G-Factor
Half Life
7.4 ± 2.9 ms
Spin3/2
Quadrupole Moment
Discovery Year2016
Parity-

67Kr Decay Modes
Decay ModeIntensity
2p (2-proton emission)37%
β+ (β+ decay; β+ = ϵ + e+)%

68Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
67.972489 ± 0.000537 Da
Mass Number68
G-Factor
0
Half Life
21.6 ± 3.3 ms
Spin0
Quadrupole Moment
0
Discovery Year2016
Parity+

68Kr Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)%
β+ p (β+-delayed proton emission)90%
p (proton emission)%

69Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
68.965496 ± 0.000322 Da
Mass Number69
G-Factor
Half Life
27.9 ± 0.8 ms
Spin5/2
Quadrupole Moment
Discovery Year1995
Parity-

69Kr Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ p (β+-delayed proton emission)94%

70Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
69.955877 ± 0.000215 Da
Mass Number70
G-Factor
0
Half Life
45 ± 0.14 ms
Spin0
Quadrupole Moment
0
Discovery Year1995
Parity+

70Kr Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ p (β+-delayed proton emission)1.3%

71Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
70.950265695 ± 0.000138238 Da
Mass Number71
G-Factor
Half Life
98.8 ± 0.3 ms
Spin5/2
Quadrupole Moment
Discovery Year1981
Parity

71Kr Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ p (β+-delayed proton emission)2.1%

72Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
71.942092406 ± 0.0000086 Da
Mass Number72
G-Factor
0
Half Life
17.16 ± 0.18 s
Spin0
Quadrupole Moment
0
Discovery Year1973
Parity+

72Kr Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

73Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
72.939289193 ± 0.000007061 Da
Mass Number73
G-Factor
Half Life
27.3 ± 1 s
Spin3/2
Quadrupole Moment
Discovery Year1972
Parity

73Kr Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ p (β+-delayed proton emission)0.25%

74Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
73.933084016 ± 0.000002161 Da
Mass Number74
G-Factor
0
Half Life
11.5 ± 0.11 m
Spin0
Quadrupole Moment
0
Discovery Year1960
Parity+

74Kr Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

75Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
74.930945744 ± 0.0000087 Da
Mass Number75
G-Factor
-0.2124 ± 0.0016
Half Life
4.6 ± 0.07 m
Spin5/2
Quadrupole Moment
1.137 ± 0.013
Discovery Year1960
Parity+

75Kr Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

76Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
75.925910743 ± 0.000004308 Da
Mass Number76
G-Factor
0
Half Life
14.8 ± 0.1 h
Spin0
Quadrupole Moment
0
Discovery Year1954
Parity+

76Kr Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

77Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
76.924669999 ± 0.0000021 Da
Mass Number77
G-Factor
-0.2332 ± 0.0012
Half Life
72.6 ± 0.9 m
Spin5/2
Quadrupole Moment
0.948 ± 0.01
Discovery Year1948
Parity+

77Kr Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

78Kr

Abundance
0.355 ± 0.003
Relative Atomic Mass
77.920366341 ± 0.000000329 Da
Mass Number78
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year1920
Parity+

78Kr Decay Modes
Decay ModeIntensity
+ (double β+ decay)%

79Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
78.920082919 ± 0.000003736 Da
Mass Number79
G-Factor
1.072 ± 0.004
Half Life
35.04 ± 0.1 h
Spin1/2
Quadrupole Moment
0
Discovery Year1948
Parity-

79Kr Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

80Kr

Abundance
2.286 ± 0.01
Relative Atomic Mass
79.91637794 ± 0.000000745 Da
Mass Number80
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year1920
Parity+

81Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
80.916589703 ± 0.000001152 Da
Mass Number81
G-Factor
-0.25914285714286 ± 0.00057142857142857
Half Life
229 ± 11 ky
Spin7/2
Quadrupole Moment
0.644 ± 0.004
Discovery Year1950
Parity+

81Kr Decay Modes
Decay ModeIntensity
ϵ (electron capture)100%

82Kr

Abundance
11.593 ± 0.031
Relative Atomic Mass
81.91348115368 ± 0.00000000591 Da
Mass Number82
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year1920
Parity+

83Kr

Abundance
11.5 ± 0.019
Relative Atomic Mass
82.914126516 ± 0.000000009 Da
Mass Number83
G-Factor
-0.21571777777778 ± 0.00000066666666666667
Half Life
Spin9/2
Quadrupole Moment
0.259 ± 0.001
Discovery Year1920
Parity+

84Kr

Abundance
56.987 ± 0.015
Relative Atomic Mass
83.91149772708 ± 0.0000000041 Da
Mass Number84
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year1920
Parity+

85Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
84.91252726 ± 0.000002147 Da
Mass Number85
G-Factor
-0.22344444444444 ± 0.000088888888888889
Half Life
10.728 ± 0.007 y
Spin9/2
Quadrupole Moment
0.443 ± 0.003
Discovery Year1940
Parity+

85Kr Decay Modes
Decay ModeIntensity
β (β decay)100%

86Kr

Abundance
17.279 ± 0.041
Relative Atomic Mass
85.91061062468 ± 0.00000000399 Da
Mass Number86
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year1920
Parity+

86Kr Decay Modes
Decay ModeIntensity
(double β decay)%

87Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
86.913354759 ± 0.000000264 Da
Mass Number87
G-Factor
-0.4088 ± 0.0008
Half Life
76.3 ± 0.5 m
Spin5/2
Quadrupole Moment
-0.3 ± 0.003
Discovery Year1940
Parity+

87Kr Decay Modes
Decay ModeIntensity
β (β decay)100%

88Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
87.914447879 ± 0.0000028 Da
Mass Number88
G-Factor
0
Half Life
2.825 ± 0.019 h
Spin0
Quadrupole Moment
0
Discovery Year1939
Parity+

88Kr Decay Modes
Decay ModeIntensity
β (β decay)100%

89Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
88.917835449 ± 0.0000023 Da
Mass Number89
G-Factor
-0.22 ± 0.002
Half Life
3.15 ± 0.04 m
Spin3/2
Quadrupole Moment
0.166 ± 0.002
Discovery Year1940
Parity+

89Kr Decay Modes
Decay ModeIntensity
β (β decay)100%

90Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
89.919527929 ± 0.000002 Da
Mass Number90
G-Factor
0
Half Life
32.32 ± 0.09 s
Spin0
Quadrupole Moment
0
Discovery Year1951
Parity+

90Kr Decay Modes
Decay ModeIntensity
β (β decay)100%

91Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
90.923806309 ± 0.0000024 Da
Mass Number91
G-Factor
-0.2332 ± 0.0008
Half Life
8.57 ± 0.04 s
Spin5/2
Quadrupole Moment
0.303 ± 0.006
Discovery Year1951
Parity+

91Kr Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%

92Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
91.926173092 ± 0.0000029 Da
Mass Number92
G-Factor
0
Half Life
1.84 ± 0.008 s
Spin0
Quadrupole Moment
0
Discovery Year1951
Parity+

92Kr Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)0.0332%

93Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
92.931147172 ± 0.0000027 Da
Mass Number93
G-Factor
-0.826 ± 0.004
Half Life
1.287 ± 0.01 s
Spin1/2
Quadrupole Moment
0
Discovery Year1951
Parity+

93Kr Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)1.95%

94Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
93.934140452 ± 0.000013 Da
Mass Number94
G-Factor
0
Half Life
212 ± 4 ms
Spin0
Quadrupole Moment
0
Discovery Year1972
Parity+

94Kr Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)1.11%

95Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
94.939710922 ± 0.00002 Da
Mass Number95
G-Factor
-0.82 ± 0.006
Half Life
114 ± 3 ms
Spin1/2
Quadrupole Moment
0
Discovery Year1994
Parity+

95Kr Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)2.87%
2n (2-neutron emission)%

96Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
95.943014473 ± 0.000020695 Da
Mass Number96
G-Factor
0
Half Life
80 ± 8 ms
Spin0
Quadrupole Moment
0
Discovery Year1994
Parity+

96Kr Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)3.7%

97Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
96.949088782 ± 0.00014 Da
Mass Number97
G-Factor
Half Life
62.2 ± 3.2 ms
Spin3/2
Quadrupole Moment
Discovery Year1997
Parity+

97Kr Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)6.7%
2n (2-neutron emission)%

98Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
97.952635 ± 0.000322 Da
Mass Number98
G-Factor
0
Half Life
42.8 ± 3.6 ms
Spin0
Quadrupole Moment
0
Discovery Year1997
Parity+

98Kr Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)7%
2n (2-neutron emission)%

99Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
98.958776 ± 0.000429 Da
Mass Number99
G-Factor
Half Life
40 ± 11 ms
Spin5/2
Quadrupole Moment
Discovery Year1997
Parity-

99Kr Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)11%
2n (2-neutron emission)%

100Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
99.962995 ± 0.000429 Da
Mass Number100
G-Factor
0
Half Life
12 ± 8 ms
Spin0
Quadrupole Moment
0
Discovery Year1997
Parity+

100Kr Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%
2n (2-neutron emission)%

101Kr

AbundanceRadioactive ☢️
Relative Atomic Mass
100.969318 ± 0.000537 Da
Mass Number101
G-Factor
Half Life
Spin5/2
Quadrupole Moment
Discovery Year2010
Parity+

101Kr Decay Modes
Decay ModeIntensity
β (β decay)%
β n (β-delayed neutron emission)%
2n (2-neutron emission)%

History

Scottish chemist Sir William Ramsay and his assistant English chemist Morris Travers discovered krypton in 1898 in London. They found krypton in the residue left from evaporating nearly all components of liquid air. William Ramsay was awarded the 1904 Nobel Prize in Chemistry for discovery of a series of noble gases, including krypton. From the Greek word kryptos, hidden

DiscoverersSir William Ramsey, M.W. Travers
Discovery LocationGreat Britain
Discovery Year1898
Etymology (Name Origin)Greek: kryptos (hidden).
PronunciationKRIP-ton (English)
Krypton is considered to be non-toxic
When ionized, krypton gas emits bright white light

Uses

Krypton is used in certain photographic flash lamps for high-speed photography. Krypton-83 has application in magnetic resonance imaging (MRI) for imaging airways. Krypton is used as a filling gas for energy-saving fluorescent lights and as an inert filling gas in incandescent bulbs. 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.

Sources

Forms 1 millionth of the atmosphere. Obtained from production of liquid air.

Abundance
Abundance in Earth's crust
0.0001 mg/kg
Abundance in Oceans
0.00021 mg/L
Abundance in Human Body
Abundance in Meteor
Abundance in Sun
Abundance in Universe
0.000004 %

Nuclear Screening Constants

1s0.7684
2p3.953
2s9.602
3d15.3741
3p15.5658
3s14.9673
4p26.2308
4s24.6844