A diamagnetic coordination complex of cobalt(III) has the formula [ Co ( en )_x( Cl )_y]^- , where 'en' represents ethylenediamine. The value of x + y is

Step-by-step solution

The oxidation state of cobalt is +3 . Let the overall charge of the complex be -1 . The charge balance equation is: +3 + x(0) + y(-1) = -1 y = 4 Cobalt(III) has a 3d^6 electronic configuration. The complex is diamagnetic, which indicates that all electrons are paired. This occurs in a strong octahedral ligand field, leading to a low-spin t_ 2g ^6 e_g^0 configuration. Thus, the coordination number of the complex is 6 . Since 'en' (ethylenediamine) is a bidentate ligand and 'Cl' is a monodentate ligand, the sum of th