• Class: Alkalines
• Period: 6
• IUPAC group: 2
• Traditional: IIa

• Discovered in: 1808 by Davy
• Origin of name: Greek: barys, (heavy)
• Historical or alternate name:

Barite or heavy spar & witherite

Silvery white, soft metal. Attacked by air and water.

• Atmosphere: ~0.0 ppm
• Primitive mantle: 5.1 ppm
• Sea water: 0.03 ppm
• Metallic meteorite: 2.270 ppm
• ConTinental crust: 250.0 ppm
• Solar photosphere: 2.09 log of abundance
• Oceanic crust: 25.0 ppm
• Solar system: 4.36 relative to Si=1.0e6

   Hazards

Poison. Soluble compounds toxic by ingestion..

• Lower:0.01
• Upper:1.0

Barium Physical Properties

 Transitional Data

• State: Solid
• Density: 3.51 g/cm3

 Molar enthalpy

• Atomization: 180.7 kJ mol-1
• Fusion: 7.66 kJ mol-1
• Vaporization: 150.9 kJ mol-1

 Transition points

• MelTing point: 998.0 K
• Boiling point: 1913.0 K
• Critical temperature: 3270.0 K

 Molar properties

• Atomic weight: 137.327 g/mole
• Molar volume: 38.399 cm3 mol-1

 Crystal structure sequence

body-centered-cubic

 Thermodynamics

• State: solid
  • Enthalpy 0
  • Gibbs function 0
  • Entropy 62.8
  • Heat Capacity 28.07

• State: gas
  • Enthalpy 180
  • Gibbs function 146
  • Entropy 170.243
  • Heat Capacity 20.786

 Miscellaneous physical

• Electrical resistivity: 50.0 µ-ohms/cm
• Debye temperature: 110.0 K
• Thermal conductivity: 18.4 W / m / K
• Coefficient of linear expansion: 20.7Coef. per K
• Mass magnetic susceptibility: 1.9e-9
• X-ray diffraction mass absorption coefficients:
• CuK: 330 (µ/p)/cm2 g-1
• MoK: 43.5 (µ/p)/cm2 g-1

Barium Chemical Properties

 Chemical basics:

• Oxidation states: +2
• Molecular wt: 137.327 g/mole

 Radii

• Covalent: 198 pm
• Atomic: 224.0 pm
• Van der Waals: pm

 Ions:

• ion: +2 pm 135.0

 Covalent bonds

 Effective nuclear charge

• Slater: 2.85
• Clementi: 7.58
• Froese-Fischer: 10.27

 Electronegativity

• Pauling: 0.9
• Allred-Rochow: 0.97

 Standard reactions

Barium Nuclear Properties

• Known 25
• Listed 10

• Known 123 - 143
• Listed 130 - 140

• % Occ.:Natural 0.106%
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life: 11.5 days
  • Decay mode: E.C., Beta+
  • Source: reactor
• Notes med

• % Occ.:Natural 0.101%
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• % Occ.:Natural
• Mossbauer NRA: 1.97
• Nuclear spin/Quantum no.: 1/2
• Radioisotopes:
  • Half-life: 10.5 years
  • Decay mode: E.C.,
  • Source: reactor
• Notes

• % Occ.:Natural 2.417%
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• % Occ.:Natural 6.592%
• Mossbauer NRA:
• Nuclear spin/Quantum no.: 3/2
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• % Occ.:Natural 7.854%
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• % Occ.:Natural 11.230%
• Mossbauer NRA:
• Nuclear spin/Quantum no.: 3/2
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• % Occ.:Natural 71.700%
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life: 12.8 days
  • Decay mode: Beta-
  • Source: reactor
• Notes

• Isotope Cross-section 1.2±0.1 barns

• Absolute sensitivity: 3.22e-4 1H=1.0
• Relative sensitivity: 4.90e-4 1H=1.0
• Receptivity: 1.83 13C=1.0
• Magnetogyric ratio: 2.6575e7 rad / T / s
• Quadropole moment: 0.18e-28 m2
• Frequency: 9.934 MHz
• Reference: BaCl2

Barium Energy Properties

Electrons

• Ground state electron configuration: [Xe] 6s2
• Electron affinity: -46 kJ mol-1
• Filling orbitals:

Spectral lines

 Ionization energies

 Atomic energy levels