Metal Complexes and the Environment: Microscale Experiments with Iron-EDTA Chelates

The presence of ligands in natural and artificial environments is increasing. Science majors need exposure to experiments that deal with ligands and complexes in the environment. Two such experiments are presented here: The dissolution of a nonsoluble polluting gas (NO) by complex formation with Iron(II)EDTA] and the decomposition of Iron(III)EDTA] by exposure to light. The experiments involve the preparation of Iron-EDTA complexes, which are then used to demonstrate the positive and negative effects of ligands in the environment. These experiments are appropriate for applied inorganic chemistry or environmental chemistry laboratories. The first one takes approximately three hours to complete, and the second takes less than two hours.