• Class: Inert Gases
• Period: 4
• IUPAC group: 18
• Traditional: 0

• Discovered in: 1898 by Ramsay, Travers
• Origin of name: Greek: kryptos, (hidden)
• Historical or alternate name:

Air to the extent of 1 ppm

Colorless, odorless, chemically inert gas. Reacts only with Fluorine.

• Atmosphere: 1.14 ppm
• Primitive mantle: ~0.0 ppm
• Sea water: 0.0003 ppm
• Metallic meteorite: 8.7 ppm
• Continental crust: 1.0E-5 ppm
• Solar photosphere: ~0.0 log of abundance
• Oceanic crust: ~0.0 ppm
• Solar system: 45.3 relative to Si=1.0e6

   Hazards

Inert nonflammable gas. Asphyxiant..

• Lower:
• Upper:

Krypton Physical Properties

 Transitional Data

• State: Gas
• Density: 3.733 g/L

 Molar enthalpy

• Atomization: 0.0 kJ mol-1
• Fusion: 1.64 kJ mol-1
• Vaporization: 9.05 kJ mol-1

 Transition points

• Melting point: 116.6 K
• Boiling point: 120.9 K
• Critical temperature: 209.4 K

 Molar properties

• Atomic weight: 83.80 g/mole
• Molar volume: 27.264 cm3 mol-1

 Crystal structure sequence

face-centered-cubic

 Thermodynamics

• State: gas
  • Enthalpy 0
  • Gibbs function 0
  • Entropy 164.082
  • Heat Capacity 20.786

 Miscellaneous physical

• Electrical resistivity: µ-ohms/cm
• Debye temperature: 72.0 K
• Thermal conductivity: 0.0095 W / m / K
• Coefficient of linear expansion: Coef. per K
• Mass magnetic susceptibility: -4.32e-9
• X-ray diffraction mass absorption coefficients:
• CuK: 108 (µ/p)/cm2 g-1
• MoK: 84.9 (µ/p)/cm2 g-1

Krypton Chemical Properties

 Chemical basics:

• Oxidation states: 0
• Molecular wt: 83.80 g/mole

 Radii

• Covalent: 189 pm
• Atomic: 202.0 pm
• Van der Waals: 198 pm

 Ions:

 Covalent bonds

 Effective nuclear charge

• Slater: 8.25
• Clementi: 9.77
• Froese-Fischer: 11.79

 Electronegativity

• Pauling:
• Allred-Rochow:

 Standard reactions

Krypton Nuclear Properties

• Known 23
• Listed 8

• Known 74 - 94
• Listed 78 - 86

• % Occ.:Natural 0.35%
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• % Occ.:Natural 2.25%
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.: 7/2
• Radioisotopes:
  • Half-life: 0.21 E6 years
  • Decay mode: E.C.,
  • Source: reactor
• Notes

• % Occ.:Natural 11.60%
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• % Occ.:Natural 11.50%
• Mossbauer NRA: 1.506
• Nuclear spin/Quantum no.: 9/2
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• % Occ.:Natural 57.00%
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.: 9/2
• Radioisotopes:
  • Half-life: 10.80 years
  • Decay mode: Beta-
  • Source: reactor
• Notes med

• % Occ.:Natural 17.30%
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• Isotope Cross-section 24.1±1.0 barns

• Absolute sensitivity: 2.17e-4 1H=1.0
• Relative sensitivity: 1.88e-3 1H=1.0
• Receptivity: 1.23 13C=1.0
• Magnetogyric ratio: -1.029e7 rad / T / s
• Quadropole moment: 0.15e-28 m2
• Frequency: 3.847 MHz
• Reference:

Krypton Energy Properties

Electrons

• Ground state electron configuration: [Ar] 3d10 4s2 4p6
• Electron affinity: -39 kJ mol-1
• Filling orbitals:

 Ionization energies

 Atomic energy levels