Geometry of Molecules & Ions

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Geometry of Molecules & Ions

  1. 1. T- 1-855-694-8886 Email- info@iTutor.com By iTutor.com
  2. 2. A central metal atom bonded to a group of molecules or ions is a metal complex. If the complex bears a charge, it is a complex ion. Compounds containing complexes are coordination compounds.
  3. 3. The molecules or ions coordinating to the metal are the ligands. They are usually anions or polar molecules.
  4. 4. Three categories of isomerization 1. Structural isomers: atoms connected in different ways 1. Coordination isomers 2. Linkage isomers 2. Geometric isomers: ligands have different spatial arrangement 1. Cis-trans isomers 2. Octahedral complex isomers 3. Optical isomers: nonsuperimposable mirror- images (enantiomers)
  5. 5. Coordination isomers Coordination ligand exchanges places w/uncoordinated counter-ion Ex: [Co(NH3)5Br]Cl vs. [Co(NH3)5Cl]Br
  6. 6. Either one of atoms in NO2 - can bond to metal When O, nitrito: ONO- When N, nitro: NO2 - Different color compounds
  7. 7. Occurs in sq-planar: MA2B2 And octahedral complexes: MA4B2
  8. 8. 8 MX3Y3 Fac (facial) isomer Three identical ligands at corners of a triangular face of octahedron Mer (meridian) isomer Three identical ligands at corners of a triangular meridian (inside octahedron)
  9. 9. Absorbs all colors-but- the one you see or Reflects most colors but absorbs the complimentary
  10. 10. The colors of complex ions are due to electronic transitions between the split d sublevel orbitals The wavelength of maximum absorbance can be used to determine the size of the energy gap between the split d sublevel orbitals Ephoton = h = hc/ =
  11. 11. The strength of the crystal field depends in large part on the ligands strong field ligands include: CN─ > NO2 ─ > en > NH3 weak field ligands include: H2O > OH─ > F─ > Cl─ > Br─ > I─ crystal field strength increases as the charge on the metal cation increases
  12. 12. The electron configuration of the metal ion with split d orbitals depends on the strength of the crystal field The 4th and 5th electrons will go into the higher energy dx2-y2 and dz2 if the field is weak and the energy gap is small – leading to unpaired electrons and a paramagnetic complex The 4th thru 6th electrons will pair the electrons in the dxy, dyz and dxz if the field is strong and the energy gap is large – leading to paired electrons and a diamagnetic complex
  13. 13. paramagnetic high-spin complex diamagnetic low-spin complex Only electron configurations d4, d5, d6, or d7 can have low or high spin
  14. 14. Because the ligand approach interacts more strongly with the planar orbitals in the tetrahedral geometry, their energies are raised Most high-spin complexes
  15. 15. d8 metals The most complex splitting pattern Most are low-spin complexes
  16. 16. Occurs when polar molecules are attracted to each other. Dipole interaction happens in water positive region of one molecule attracts the negative region of another molecule.
  17. 17. Occur when polar molecules are attracted to each other. Slightly stronger than dispersion forces. Opposites attract, but not completely hooked like in ionic solids. H F H F
  18. 18. Call us for more Information: www.iTutor.com 1-855-694-8886 Visit

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