Separation of Complex Cations of Chromium(III) by Ion Exchange Essay - 1

Separation of Complex Cations of Chromium(III) by Ion Exchange Chromatography - Essay Example The relative amount of divinyl-benzene affects the physical properties and solubility of the resins. 9. After the solution is drained to the resin level, the column is washed with HCIO4 until the un-reacted [CrCl2 (H2O) 4] has been eluted to approximately 5 cm3 of the intensely colored fraction and the UV visible spectrum measured. Chromium (III) is the simplest ion that chromium forms in solution. Chromium (III) prefers to form octahedral complexes whose color is determined by the ligands attached to the chromium center. It forms different complexes under different conditions. . Regarding the ion exchange process for Chromium (III), the ion exchange resins used is SO3H group. Aqueous solutions of the complexes trans‑[CrCl2(H2O)4] Cl, [CrCl(H2O)5]Cl2 and [Cr(H2O)6]Cl3 will be isolated in a pure state based on their different affinities for a cationic exchange resin. Only a single beam of UV-VIs is used to determine 10 Dq. They have â€Å"the  ligand field  splitting energy† which helps to determine this easily and quickly. This is because there is no d-d electron transition as the d orbitals are completely filled and UV-VIs bands are not observed (Pantsar-Kallio 1997).   As a result, two bands are observed in the region 350 to 750 nm. This band energy is used to identify and characterize complex ions. The peak tells us that how much energy is absorbed at each wavelength of the UV. The longest wavelength band (distance between two adjacent peaks on graph) of the two has energy approximately equal to 10Dq for the complex ion. The relative crystal field strength of H2O is high than Cl because Cl ligand has a weak field ligand and determines a smaller value of 10 Dq while [Cr (H2O) 6]3+ has the highest 10Dq because there is no Cl ligand in it only H2O is present which is a strong field ligand and determines a higher value of 10 Dq. From the above experiment we may conclude that in the ion exchange method of