Consider the tetrahedral complex ion [ CoCl ₄ ]²⁻ . Ignoring the pairing energy, the magnitude of the crystal field stabilization energy (CFSE) for this complex is x _ t . The value of 10x is _______.

Step-by-step solution

The central metal ion in [ CoCl ₄ ]²⁻ is Co ²⁺ . The electronic configuration of Co ²⁺ is [ Ar ] 3 d ⁷ . For a tetrahedral complex, the d-orbital splitting is inverted compared to octahedral complexes, with the e set at a lower energy ( -0.6 _ t ) and the t ₂ set at a higher energy ( +0.4 _ t ). Tetrahedral complexes are generally high-spin. The filling of 7 electrons in the tetrahedral field is e ⁴ t ₂³ . CFSE = [4 (-0.6) + 3 (+0.4)] _ t = (-2.4 + 1.2) _ t = -1.2 _ t . The magnitude of CFSE is 1.2 _ t , so x = 1.2