AIIMS 2018 Chemistry Complex Formation MCQ Question

The complex [Cr(NH₃)₆]³⁺ is octahedral due to the coordination number of 6, which indicates that six ammonia (NH₃) ligands surround the central chromium ion (Cr³⁺) in a symmetrical arrangement. This geometry arises from the d²sp³ hybridization of the metal ion, leading to bond angles of approximately 90° between the ligands. Options B (tetrahedral) and C (square planar) are incorrect because they correspond to coordination numbers of 4 and 4, respectively, while option D (linear) is not applicable as it suggests a coordination number of 2, which does not fit the given complex.