An unknown coordination compound with the formula [ M ( en )₂ Cl ₂ ] Cl is found to be diamagnetic. The metal M belongs to the 3 d transition series. Identify the metal M , the hybridisation of the complex ion, and the total number of stereoisomers it can exhibit.

Step-by-step solution

The complex is [ M ( en )₂ Cl ₂ ] Cl . The complex ion is [ M ( en )₂ Cl ₂ ]⁺ . Let the oxidation state of M be x . Since ethylenediamine (en) is a neutral bidentate ligand and chloride is -1 , we have x + 2(0) + 2(-1) = +1 x = +3 . The metal M is in the +3 oxidation state. Since the complex is diamagnetic, it must have 0 unpaired electrons. For an octahedral complex (coordination number = 6 ) of a 3 d transition metal, a diamagnetic nature is only possible for a d ⁶ low-spin configuration ( t _ 2 g ⁶ e _ g ⁰ ). Th