What are the oxidation state and coordination number of the central metal ion in the complex [Cr(EDTA)]⁻ ? (where EDTA is ethylenediaminetetraacetate)

Step-by-step solution

Let the oxidation state of Cr be x . The ligand EDTA (ethylenediaminetetraacetate) carries a charge of -4 . The sum of oxidation states must equal the net charge on the complex ion: x + (-4) = -1 x = +3 EDTA is a hexadentate ligand, meaning it forms 6 coordinate bonds with the central metal ion (through two nitrogen and four oxygen donor atoms). Therefore, the coordination number of Cr in this complex is 6. The oxidation state is +3 and the coordination number is 6. Answer: +3 and 6