Which of the following coordination entities are more stable for strong forld as compared to weak field cases ?

Options

A. `d^(1) - d^(3)`
B. `d^(4) - d^(7)`
C. `d^(8) - d^(10)`
D. `d^(5) - d^(9)`

Answer

B

Explanation

A choice between high spin and low spin electron configuration only for complexes of metal ions with four to seven d electrons, so called `d^(4) - d^(7)` complexes. No such distinction (i.e., the high spin and low spin octahedral complexes) can be made for `d^(1), d^(2), d^(3), d^(8), d^(9)` and `d^(10)` . For `d^(1)-d^(3)` and `d^(8)-d^(10)` complexes, only one ground state electron configuration is possible. In `d^(1)-d^(3)` complexes, all the electrons, ocupy the lower energy `t_(2g)` orbitals, independent of the value of `Delta`. In `d^(8)-d^(10)` complexes, the lower energy set of `t_(2g)` orbitals is filled with three pairs of electrons, while the higher energy `e_(g)` set contains two, three, or four electrons, again independent of the vlue of `Delta` . Calculation of CFSH shown that coordination entities with four to seven d electrons are more stable for strong field as compared to weak field cases.