• Class: Transition Metals
• Period: 5
• IUPAC group: 9
• Traditional: VIII

• Discovered in: 1803 by Wollaston
• Origin of name: Greek: rhodon, (rose)
• Historical or alternate name:

Platinum ores & Copper-Nickel sulfide ores

Hard, silvery, lustrous metal. Inert in air and acids. Reacts with fused alkalis.

• Atmosphere: ~0.0 ppm
• Primitive mantle: 0.0017 ppm
• Sea water: 1e-10 ppm
• Metallic meteorite: 0.134 ppm
• Continental crust: 0.005 ppm
• Solar photosphere: 1.40 log of abundance
• Oceanic crust: 0.0002 ppm
• Solar system: 0.344 relative to Si=1.0e6

   Hazards

Toxic by inhalation. Soluble compounds highly toxic..

• Lower:
• Upper:

Rhodium Physical Properties

 Transitional Data

• State: Solid
• Density: 12.4 g/cm3

 Molar enthalpy

• Atomization: 555.59 kJ mol-1
• Fusion: 21.55 kJ mol-1
• Vaporization: 494.34 kJ mol-1

 Transition points

• Melting point: 2239.0 K
• Boiling point: 4000.0 K
• Critical temperature: 7000.0 K

 Molar properties

• Atomic weight: 102.9055 g/mole
• Molar volume: 8.334 cm3 mol-1

 Crystal structure sequence

face-centered-cubic

 Thermodynamics

• State: solid
  • Enthalpy 0
  • Gibbs function 0
  • Entropy 31.51
  • Heat Capacity 24.98

• State: gas
  • Enthalpy 556.9
  • Gibbs function 510.8
  • Entropy 185.808
  • Heat Capacity 21.012

 Miscellaneous physical

• Electrical resistivity: 4.51 µ-ohms/cm
• Debye temperature: 480.0 K
• Thermal conductivity: 150.0 W / m / K
• Coefficient of linear expansion: 8.2Coef. per K
• Mass magnetic susceptibility: 1.36e-8
• X-ray diffraction mass absorption coefficients:
• CuK: 194 (µ/p)/cm2 g-1
• MoK: 22.6 (µ/p)/cm2 g-1

Rhodium Chemical Properties

 Chemical basics:

• Oxidation states: +3 +4 +5
• Molecular wt: 102.9055 g/mole

 Radii

• Covalent: 125 pm
• Atomic: 134.0 pm
• Van der Waals: pm

 Ions:

• ion: +3 pm 66.5
• ion: +4 pm 60.0
• ion: +5 pm 55.0

 Covalent bonds

 Effective nuclear charge

• Slater: 3.90
• Clementi: 7.64
• Froese-Fischer: 10.85

 Electronegativity

• Pauling: 2.2
• Allred-Rochow: 1.45

 Standard reactions

Rhodium Nuclear Properties

• Known 20
• Listed 5

• Known 97 - 110
• Listed 99 - 107

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life: 16.0 days
  • Decay mode: E.C., Beta+
  • Source: reactor
• Notes

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.: 1/2
• Radioisotopes:
  • Half-life: 3.3 years
  • Decay mode: E.C.,
  • Source: reactor
• Notes

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.: 6/0
• Radioisotopes:
  • Half-life: 206.0 days
  • Decay mode: E.C., Beta+ Beta-
  • Source: reactor
• Notes

• % Occ.:Natural 100.0%
• Mossbauer NRA:
• Nuclear spin/Quantum no.: 1/2
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

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

• Isotope Cross-section 150±5 barns

• Absolute sensitivity: 3.11e-5 1H=1.0
• Relative sensitivity: 3.11e-5 1H=1.0
• Receptivity: 0.177 13C=1.0
• Magnetogyric ratio: -0.8520e7 rad / T / s
• Quadropole moment: m2
• Frequency: 3.172 MHz
• Reference: mer-[RhCl3(SMe2)3]

Rhodium Energy Properties

Electrons

• Ground state electron configuration: [Kr] 4d8 5s1
• Electron affinity: 162 kJ mol-1
• Filling orbitals:

Spectral lines

 Ionization energies

 Atomic energy levels