How do I know if an atom has degenerate orbitals?

My Understanding

I understand that degenerate orbitals mean orbitals that have the same energy level for the same n. However, how do I distinguish between an atom that has degenerate orbitals?

EDIT: Example of non-degenerate orbitals (Source)


  • $\begingroup$ Degenerate orbitals = same energy level. Everything else depends on conditions (number of electrons already present, external fields, etc...) $\endgroup$ – ssavec Apr 14 '14 at 7:30

If I understand your question correctly: Isolated atoms always have degenerate orbitals: the p orbitals 3-times degenerate, the d orbital 5-times degenerate, and the interaction with a crystal field / ligand field/ presence of other atoms and their electronic occupation that split this degeneracy.

If I misunderstood your question, please explain what you would like to distinguish from what?

  • $\begingroup$ Check the image I have attached. I suppose it describes the energy levels for orbitals for a single atom... so I don't understand what you mean or what is going on. $\endgroup$ – user2789433 Apr 14 '14 at 5:03
  • 1
    $\begingroup$ In addition to crystal or ligand field: Any field whatsoever may split degenerate orbitals. $\endgroup$ – Martin - マーチン Apr 14 '14 at 5:29
  • $\begingroup$ OK, so those are the orbital energy levels, correct. What is your question? $\endgroup$ – Greg Apr 15 '14 at 6:00

The ground state of any atom has degenerate sub-shell orbitals; however anything that increases the energy of one orbital more than the others, be it a steric effect or a field effect will break the degeneracy. There is only one s orbital so there isn't really anything for it to be degenerate with (ignoring hybridisation), p orbitals however since there are three of them AND they are mutually perpendicular there is opportunity for something to effect one p orbital more than the other two raising it's energy and breaking degeneracy. An example would be a magnetic field which running perpendicular to one orbital will have no effect but will increase the energy of the other two orbitals since they are mutually perpendicular. Another interesting example occurs in ligand field theory - http://chemwiki.ucdavis.edu/Inorganic_Chemistry/Crystal_Field_Theory/High_Spin_and_Low_Spin_Complexes


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