Ruthenium: properties of free atoms

Ruthenium atoms have 44 electrons and the shell structure is

The ground state electron configuration of ground state gaseous neutral ruthenium is  [Kr].4d75s1 and the term symbol is  5F5.

Atomic spectrum


A representation of the atomic spectrum of ruthenium.

Electronic configuration of neutral atomic ruthenium

Electronic configuration of ruthenium

The electronic configuration of ruthenium.

Kossel shell structure of ruthenium

The Kossel shell structure of ruthenium.

Ionisation Energies and electron affinity

The electron affinity of ruthenium is 101.3 kJ mol‑1. The ionisation energies of ruthenium are given below.

Ionisation energies of ruthenium
Ionisation energy number Enthalpy / kJ mol‑1

Effective Nuclear Charges

The following are "Clementi-Raimondi" effective nuclear charges, Zeff. Follow the hyperlinks for more details and for graphs in various formats.

Effective nuclear charges for ruthenium
2s32.38 2p39.95  
3s27.60 3p27.22 3d29.36  
4s17.66 4p16.43 4d12.81 4f(no data)
5s6.48 5p(no data) 5d(no data)  
6s(no data) 6p(no data)  


These effective nuclear charges, Zeff, are adapted from the following references:

  1. E. Clementi and D.L.Raimondi, J. Chem. Phys. 1963, 38, 2686.
  2. E. Clementi, D.L.Raimondi, and W.P. Reinhardt, J. Chem. Phys. 1967, 47, 1300.

Electron binding energies

Electron binding energies for ruthenium. All values of electron binding energies are given in eV. The binding energies are quoted relative to the vacuum level for rare gases and H2, N2, O2, F2, and Cl2 molecules; relative to the Fermi level for metals; and relative to the top of the valence band for semiconductors.
Label Orbital eV [literature reference]
K 1s22117 [1]
L I2s3224 [1]
L II2p1/22967 [1]
L III2p3/22838 [1]
M I3s586.1 [2]
M II3p1/2483.3 [3]
M III3p3/2461.5 [3]
M IV3d3/2284.2 [3]
M V3d5/2280 [3]
N I4s75 [3]
N II4p1/246.3 [3]
N III4p3/243.2 [3]


I am grateful to Gwyn Williams (Jefferson Laboratory, Virginia, USA) who provided the electron binding energy data. The data are adapted from references 1-3. They are tabulated elsewhere on the WWW (reference 4) and in paper form (reference 5).


  1. J. A. Bearden and A. F. Burr, "Reevaluation of X-Ray Atomic Energy Levels," Rev. Mod. Phys., 1967, 39, 125.
  2. M. Cardona and L. Ley, Eds., Photoemission in Solids I: General Principles (Springer-Verlag, Berlin) with additional corrections, 1978.
  3. Gwyn Williams WWW table of values
  4. D.R. Lide, (Ed.) in Chemical Rubber Company handbook of chemistry and physics, CRC Press, Boca Raton, Florida, USA, 81st edition, 2000.
  5. J. C. Fuggle and N. Mårtensson, "Core-Level Binding Energies in Metals," J. Electron Spectrosc. Relat. Phenom., 1980, 21, 275.

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