• Class: Transition Metals
• Period: 5
• IUPAC group: 7
• Traditional: VIIa

• Discovered in: 1937 by Perrier, Segre`
• Origin of name: Greek: technetos, (artificial)
• Historical or alternate name:

Found only in the spectrum of S-, M- & N-type stars

Silver solid metal or grey powder. Resists oxydation but tarnishes in moist air and burns in high Oxygen envIronment.

• Atmosphere: ~0.0 ppm
• Primitive mantle: ~0.0 ppm
• Sea water: ~0.0 ppm
• Metallic meteorite: ~0.0 ppm
• Continental crust: ~0.0 ppm
• Solar photosphere: ~0.0 log of abundance
• Oceanic crust: ~0.0 ppm
• Solar system: ~0.0 relative to Si=1.0e6

   Hazards

Radioactive..

• Lower:
• Upper:

Technetium Physical Properties

 Transitional Data

• State: Solid
• Density: 11.5 g/cm3

 Molar enthalpy

• Atomization: 678.0 kJ mol-1
• Fusion: 23.81 kJ mol-1
• Vaporization: 585.22 kJ mol-1

 Transition points

• Melting point: 2445.0 K
• Boiling point: 5150.0 K
• Critical temperature: 11500.0 K

 Molar properties

• Atomic weight: 98.9063 g/mole
• Molar volume: 8.644 cm3 mol-1

 Crystal structure sequence

hexagonal-close-packed

 Thermodynamics

• State: solid
  • Enthalpy 0
  • Gibbs function 0
  • Entropy
  • Heat Capacity 25

• State: gas
  • Enthalpy 678
  • Gibbs function
  • Entropy 181.07
  • Heat Capacity 20.79

 Miscellaneous physical

• Electrical resistivity: 16.9 µ-ohms/cm
• Debye temperature: 453.0 K
• Thermal conductivity: 50.6 W / m / K
• Coefficient of linear expansion: Coef. per K
• Mass magnetic susceptibility: 3.1e-8
• X-ray diffraction mass absorption coefficients:
• CuK: 172 (µ/p)/cm2 g-1
• MoK: 19.7 (µ/p)/cm2 g-1

Technetium Chemical Properties

 Chemical basics:

• Oxidation states: +4 +6 +7
• Molecular wt: 98.9063 g/mole

 Radii

• Covalent: pm
• Atomic: 135.0 pm
• Van der Waals: pm

 Ions:

• ion: +4 pm 64.5
• ion: +5 pm 60.0
• ion: +7 pm 56.0

 Covalent bonds

 Effective nuclear charge

• Slater: 3.60
• Clementi: 7.23
• Froese-Fischer: 10.28

 Electronegativity

• Pauling: 1.9
• Allred-Rochow: 1.36

 Standard reactions

Technetium Nuclear Properties

• Known 23
• Listed 3

• Known 92 - 107
• Listed 97 - 99

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.: 9/2
• Radioisotopes:
  • Half-life: 2.60 E6 years
  • Decay mode: E.C.,
  • Source: reactor
• Notes

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.: 6/0
• Radioisotopes:
  • Half-life: 4.20 E6 years
  • Decay mode: Beta-
  • Source: reactor
• Notes

• % Occ.:Natural
• Mossbauer NRA: 22.51
• Nuclear spin/Quantum no.: 9/2
• Radioisotopes:
  • Half-life: 0.21 E6 years
  • Decay mode: Beta-
  • Source: reactor
• Notes med

• Isotope 99Cross-section 22±3 barns

• Absolute sensitivity: 1H=1.0
• Relative sensitivity: 1H=1.0
• Receptivity: 13C=1.0
• Magnetogyric ratio: 6.0503e7 rad / T / s
• Quadropole moment: -0.13e-28 m2
• Frequency: 22.508 MHz
• Reference: TcO4-

Technetium Energy Properties

Electrons

• Ground state electron configuration: [Kr] 4d5 5s2
• Electron affinity: 96 kJ mol-1
• Filling orbitals:

 Ionization energies

 Atomic energy levels