• Class: AcTinides
• Period: 7
• IUPAC group: 3
• Traditional: IIIa

• Discovered in: 1913 by Fajans and Gohring
• Origin of name: Greek: protos, (first)
• Historical or alternate name:

Pitchblende

Silvery metal. Resists alkalis; reacts with Oxygen and acids. Attacked by steam.

• Atmosphere: ~0.0 ppm
• Primitive mantle: ~0.0 ppm
• Sea water: 2e-12 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

Highly radiotoxic. Radioactive. Carcinogen..

• Lower:
• Upper:

Protactinium Physical Properties

 Transitional Data

• State: Solid
• Density: 15.37 g/cm3

 Molar enthalpy

• Atomization: 607.0 kJ mol-1
• Fusion: 16.7 kJ mol-1
• Vaporization: 481 kJ mol-1

 Transition points

• MelTing point: 1825.0 K
• Boiling point: 4500.0 K
• Critical temperature: 14000.0 K

 Molar properties

• Atomic weight: 231.03588 g/mole
• Molar volume: 15.278 cm3 mol-1

 Crystal structure sequence

body-centered-tetragonal <1443 K < body-centered-cubic < melTing point

 Thermodynamics

• State: solid
  • Enthalpy 0
  • Gibbs function 0
  • Entropy 51.9
  • Heat Capacity 28

• State: gas
  • Enthalpy 607
  • Gibbs function 563
  • Entropy 198.05
  • Heat Capacity 22.93

 Miscellaneous physical

• Electrical resistivity: 19.1 µ-ohms/cm
• Debye temperature: K
• Thermal conductivity: W / m / K
• Coefficient of linear expansion: Coef. per K
• Mass magnetic susceptibility:
• X-ray diffraction mass absorption coefficients:
• CuK: (µ/p)/cm2 g-1
• MoK: (µ/p)/cm2 g-1

Protactinium Chemical Properties

 Chemical basics:

• Oxidation states: +3 +4 +5
• Molecular wt: 231.03588 g/mole

 Radii

• Covalent: pm
• Atomic: 163.0 pm
• Van der Waals: pm

 Ions:

• ion: +3 pm 104.0
• ion: +4 pm 90.0
• ion: +5 pm 78.0

 Covalent bonds

 Effective nuclear charge

• Slater: 1.80
• Clementi:
• Froese-Fischer:

 Electronegativity

• Pauling: 1.4
• Allred-Rochow: 1.14

 Standard reactions

Protactinium Nuclear Properties

• Known 14
• Listed 3

• Known 225 - 237
• Listed 230 - 233

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life: 17.4 days
  • Decay mode: E.C. Beta- alpha,
  • Source:
• Notes

• % Occ.:Natural 100.0%
• Mossbauer NRA: 13.5
• Nuclear spin/Quantum no.: 3/2
• Radioisotopes:
  • Half-life: 328.0 centuries
  • Decay mode: alpha,
  • Source:
• Notes

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life: 27.0 days
  • Decay mode: Beta-
  • Source:
• Notes

• Isotope 231Cross-section 200±10 barns

Protactinium Energy Properties

Electrons

• Ground state electron configuration: [Rn] 5f2 6d1 7s2
• Electron affinity: kJ mol-1
• Filling orbitals:

 Ionization energies

 Atomic energy levels