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Unformatted text preview: Results and Discussion: Transition metal complexes come in a variety of colors which arise from the absorption of visible light by the complexes. The color of the light absorbed is complementary to the color that is seen. The wavelength of the colors of the absorbed light can be calculated by the difference in energy (E) using the equation E = hc / . The different energy levels that arise from transition metal complexes can be explained by the crystal field theory. The crystal field theory explains that when the negatively charged ligands are brought near the transition metal, the energies of the five degenerate d orbitals change by different amounts. The difference in energy of the orbitals is called the crystal field splitting (). The magnitude of the crystal field splitting depends on the identity of the transition metal and the ligand. If the ligand is kept constant, the crystal field splitting varies according to a certain order called the spectrochemical series. The series increases in the following order Br- < Cl- < F- < H 2 O < NH 3 An unidentified sample of one of the previous complexes (Complex B) was synthesized and purified in this lab by my group. The other (Complex A) was synthesized and purified by other groups in the lab. The wavelengths of maximum absorbance of these two complexes along wit the remaining (Complexes C, D & E) were measured. The complexes all have the general formula Co(NH...
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This lab report was uploaded on 09/26/2007 for the course CHEM 2070 taught by Professor Chirik,p during the Fall '05 term at Cornell University (Engineering School).
- Fall '05
- Chemistry, NH3, spectrochemical series, maximum absorbance, crystal field splitting, Purification of Complex B