Question
[ Ni ( PPh _ 3 )_ 2 Cl _ 2 ] is a paramagnetic complex. Identify the INCORRECT statements about this complex. A. The complex exhibits geometrical isomerism. B. The complex is white in colour. C. The calculated spin-only magnetic moment of the complex is 2.84 BM . D. The calculated CFSE (Crystal Field Stabilization Energy) of Ni in this complex is -0.8 _ o . E. The geometrical arrangement of ligands in this complex is similar to that in Ni ( CO )_ 4 . Choose the correct answer from the options given below :
Step-by-step solution
In [Ni(PPh_3)_2Cl_2], Nickel is in +2 oxidation state. Ni^ 2+ has a 3d^8 electronic configuration. The complex is given as paramagnetic. For a 4-coordinate d^8 system, paramagnetism implies a tetrahedral geometry (sp^3 hybridization) with two unpaired electrons. Statement A: Tetrahedral complexes of the type [MA_2B_2] do not exhibit geometrical isomerism because all positions are adjacent to each other. Thus, A is incorrect. Statement B: Most Ni(II) complexes are colored due to d-d transitions. [Ni(PPh_3)_2Cl_2] is a dark blue/green crystalline solid, not white. Thus, B is incorrect. Statement C: With 2 unpaired electrons, the spin-only magnetic moment = n(n+2) = 2(2+2) = 8 2.83 BM. Thus, C is correct. Statement D: For a tetrahedral complex with d^8 configuration, the CFSE is calculated as CFSE = [(-0.6 4) + (0.4 4)] _t = -0.8 _t. The statement mentions -0.8 _o, which is incorrect as the complex is tetrahedral, not octahedral. Thus, D is incorrect. Statement E: Ni(CO)_4 is a tetrahedral complex (sp^3 hybridization). Since [Ni(PPh_3)_2Cl_2] is also tetrahedral, their geometrical arrangements are similar. Thus, E is correct. The incorrect statements are A, B, and D.