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Homework Help: Crystal Field Model

  1. Apr 8, 2007 #1
    1. The problem statement, all variables and given/known data

    Which of the following are true for the Crystal Field Model of an octahedral complex ion? Consider ions to be from first-row transition metals.

    a) Two of the 3d orbitals point directly at ligands

    b) t2 orbitals are less stable than e orbitals

    c) A large crystal field splitting energy results in a diamagnetic complex

    d) The high-spin case gives maximum unpaired electrons

    e) For a given ligand, Fe3+ increases splitting less than Fe2+

    f) Cl- causes a greater increase in the crystal field splitting enery than does H2O

    g) The splitting of energy (E) of 3d orbitals occurs in the ligands

    2. Relevant equations

    3. The attempt at a solution

    I put acde and I am pretty sure I am right, what am I doing wrong?
  2. jcsd
  3. Apr 8, 2007 #2
    The statement c isn't technically right and g is unclearly worded to me.

    For statement C if there are an odd number of electrons it is still diamagnetic. By most standards diamagnetic means no unpaired electrons and if there are an odd number electrons it gonna have to be unpaired. A large splitting energy makes it hard to move the electons up in energy to the Eg orbitals but the unpaired electron can occur in T2g orbitals

    Statement G: Crystal field theory assumes coulombic repulsion. The ligands attach on the axis making a higher electron density on those 2 d orbitals. This increases the repulsion and that is why those two orbitals split and become higher in energy. So in a way the splitting energy does come the ligands
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