• Class: Alkalis
• Period: 6
• IUPAC group: 1
• Traditional: Ia

• Discovered in: 1860 by Bunsen, Kirchhoff
• Origin of name: LaTin: caesius, (sky blue)
• Historical or alternate name: (or Caesium)

Lepidolite & polucite

Very soft, Silvery white metal. Reacts readily with Oxygen. Reacts explosively with water.

• Atmosphere: ~0.0 ppm
• Primitive mantle: 0.018 ppm
• Sea water: 0.0005 ppm
• Metallic meteorite: 0.186 ppm
• ConTinental crust: 1.0 ppm
• Solar photosphere: <1.9 log of abundance
• Oceanic crust: 0.030 ppm
• Solar system: 0.372 relative to Si=1.0e6

   Hazards

Metal reacts explosively with water..

• Lower:0.01
• Upper:1.0

Cesium Physical Properties

 Transitional Data

• State: Liquid
• Density: 1.8785 g/cm3

 Molar enthalpy

• Atomization: 77.580 kJ mol-1
• Fusion: 2.09 kJ mol-1
• Vaporization: 66.5 kJ mol-1

 Transition points

• MelTing point: 301.55 K
• Boiling point: 942.5 K
• Critical temperature: 2057.0 K

 Molar properties

• Atomic weight: 132.90543 g/mole
• Molar volume: 70.168 cm3 mol-1

 Crystal structure sequence

body-centered-cubic

 Thermodynamics

• State: solid
  • Enthalpy 0
  • Gibbs function 0
  • Entropy 85.23
  • Heat Capacity 32.17

• State: gas
  • Enthalpy 76.065
  • Gibbs function 49.121
  • Entropy 175.595
  • Heat Capacity 20.786

 Miscellaneous physical

• Electrical resistivity: 20.0 µ-ohms/cm
• Debye temperature: 33.0 K
• Thermal conductivity: 35.9 W / m / K
• Coefficient of linear expansion: Coef. per K
• Mass magnetic susceptibility: 2.8e-9
• X-ray diffraction mass absorption coefficients:
• CuK: 318 (µ/p)/cm2 g-1
• MoK: 41.3 (µ/p)/cm2 g-1

Cesium Chemical Properties

 Chemical basics:

• Oxidation states: +1
• Molecular wt: 132.90543 g/mole

 Radii

• Covalent: 235 pm
• Atomic: 272.0 pm
• Van der Waals: 262 pm

 Ions:

• ion: +1 pm 167.0

 Covalent bonds

 Effective nuclear charge

• Slater: 2.20
• Clementi: 6.36
• Froese-Fischer: 8.56

 Electronegativity

• Pauling: 0.7
• Allred-Rochow: 0.86

 Standard reactions

Cesium Nuclear Properties

• Known 22
• Listed 7

• Known 123 - 144
• Listed 131 - 137

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life: 9.69 days
  • Decay mode: E.C.,
  • Source: reactor
• Notes med

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life: 6.47 days
  • Decay mode: E.C., Beta+ Beta-
  • Source: reactor
• Notes

• % Occ.:Natural 100.0%
• Mossbauer NRA: 13.0
• Nuclear spin/Quantum no.: 7/2
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.: 4/0
• Radioisotopes:
  • Half-life: 2.06 years
  • Decay mode: Beta- Beta+
  • Source: reactor
• Notes

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.: 7/2
• Radioisotopes:
  • Half-life: 2.00 E6 years
  • Decay mode: Beta-
  • Source: reactor
• Notes

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life: 13.20 days
  • Decay mode: Beta-
  • Source: reactor
• Notes

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.: 7/2
• Radioisotopes:
  • Half-life: 30.17 years
  • Decay mode: Beta-
  • Source: reactor
• Notes med

• Isotope Cross-section 30.0±1.5 barns

• Absolute sensitivity: 4.74e-2 1H=1.0
• Relative sensitivity: 4.74e-2 1H=1.0
• Receptivity: 269 13C=1.0
• Magnetogyric ratio: 3.5087e7 rad / T / s
• Quadropole moment: -3.0e-31 m2
• Frequency: 13.117 MHz
• Reference: 0.5M CsBr

Cesium Energy Properties

Electrons

• Ground state electron configuration: [Xe] 6s1
• Electron affinity: 45.5 kJ mol-1
• Filling orbitals:

Spectral lines

 Ionization energies

 Atomic energy levels