Coordination Chem, Spectroscopic/Magnetic Properties

• What is a coordination sphere?

  central metal plus the ligands coordination to it
• What is the coordination number?

  number of donor atoms bonded to the central metal
• What are the characteristics of coordination number 2:

  180 degrees, shape is linear
• What are the characteristics of the coordination number 4:

  low oxidation number (0,+1) or d0/d10, 109.5 degrees = tetrahedral 90 degrees and d8 = square planner
• What are the characteristics of coordination number 6:


  90 degrees, octahedral
• For anionic (-) complexes, you replace the metal name with the stem/root with "ate" ending
• What is crystal field theory?

  A theory that explains the splitting of d orbitals in a metal complex due to the presence of ligands.
• Distance (energy) between the eg and the t2g is the octahedral spliting (delta o)
• weak field ligands leads to smaller delta(o) splitting
• Stronger field ligands lead to a large delta(o) splitting
• What is a spectro-chemical series?

  Order of ligands based on their ability to split d-orbitals in a complex.
• What is Hund's rule?

  Electrons fill orbitals of the same energy level one at a time before pairing up.
• Tetrahedral complexes exhibit tetrahedral splitting (delta o)
• Unpaired spins are paramagnetic (attracted to magnets)
• All paired spins are called diamagnetic (slightly repelled by magnets)
• Interaction strengths with magnet increases with the number of spins
• High spins have small delta(o)
• Low spins have large delta(o)
• A high spin has more unpaired electrons than low spin
• What's the Spectro series from weakest to strongest ligand

  I- < Br- < Cl- < OH- < F- < H2O < NH3 < en < CN- < CO