Cobalt Complexes
Cobalt Complexes
Lab 4
Cobalt and its slew of complex children
Abstract: Through a series of substitution reactions, different cobalt ammine complexes were created. These complexes were analyzed via, precipitation and gravimetric measures to determine that the substitution reactions that occurred.
Introduction: Coordination chemistry is an important part of inorganic chemistry that involves the association and dissociation of ligands to a metal. The size, shape, and nucleophilic strength of a ligand will determine if a substitution reaction will potentially take place. Also, the charge, size, and oxidation state of the metal will determine how well substitution occurs. Associative substitution occurs when the nucleophilic ligand coordinates before the replaced ligand leaves the complex. Dissociation occurs when the replaced ligand spontaneously breaks away from the metal leaving a vacancy that is filled by the replacement ligand. Under various conditions, Cobalt (III) is able to undergo substitution of its ligands. In this lab, carbonatotetraamminecobalt (III) nitrate was made. Substitution reactions using chloride, nitrite, and water were performed to make other Cobalt (III) complexes. They were gravimetrically measured to determine yields and properties.
Experimental Step 1: 20.0053g (0.2101mol) of (NH4)2CO3 was added to 60mL of concentrated (14.8M) NH4OH solution. This was stirred for several minutes before adding 15.0035g (0.05155mol) of Co(NO3)2-(H2O)6 that had been dissolved in 30mL of distilled H2O. To this resulting solution was added 8mL of a 30% solution of H2O2. H2O2 was handled with extreme care and with gloves due to its corrosive nature. This total solution was then concentrated by evaporation over a hot plate with a steady flow of N2 to increase evaporation speed. This solution was kept just under boiling for about an hour during which time another 5 grams of (NH4)2CO3 added. At the end of the hour
Lab 4
Cobalt and its slew of complex children
Abstract: Through a series of substitution reactions, different cobalt ammine complexes were created. These complexes were analyzed via, precipitation and gravimetric measures to determine that the substitution reactions that occurred.
Introduction: Coordination chemistry is an important part of inorganic chemistry that involves the association and dissociation of ligands to a metal. The size, shape, and nucleophilic strength of a ligand will determine if a substitution reaction will potentially take place. Also, the charge, size, and oxidation state of the metal will determine how well substitution occurs. Associative substitution occurs when the nucleophilic ligand coordinates before the replaced ligand leaves the complex. Dissociation occurs when the replaced ligand spontaneously breaks away from the metal leaving a vacancy that is filled by the replacement ligand. Under various conditions, Cobalt (III) is able to undergo substitution of its ligands. In this lab, carbonatotetraamminecobalt (III) nitrate was made. Substitution reactions using chloride, nitrite, and water were performed to make other Cobalt (III) complexes. They were gravimetrically measured to determine yields and properties.
Experimental Step 1: 20.0053g (0.2101mol) of (NH4)2CO3 was added to 60mL of concentrated (14.8M) NH4OH solution. This was stirred for several minutes before adding 15.0035g (0.05155mol) of Co(NO3)2-(H2O)6 that had been dissolved in 30mL of distilled H2O. To this resulting solution was added 8mL of a 30% solution of H2O2. H2O2 was handled with extreme care and with gloves due to its corrosive nature. This total solution was then concentrated by evaporation over a hot plate with a steady flow of N2 to increase evaporation speed. This solution was kept just under boiling for about an hour during which time another 5 grams of (NH4)2CO3 added. At the end of the hour