The ion `[Co(NH_(3))_(6)]^(+)` is octahedral and high spin. This complex is

Options

A. paramagnetic, with 1 unpaired electrons
B. paramagnetic, with 3 unpaired electrons
C. paramagnetic, with 4 unpaired electrons
D. paramagnetic, with 5 unpaired electrons

Answer

B

Explanation

The complex ion is high spin, i.e., the electrons are arranged so that they remain unpaired as much as possible. This can be possible, if the d-orbitals involved are from higher energy shell than from ns and np-orbitals. In otherwords, in a high spin complex, (n-1)d-orbitals are not involved in the hybridization.

High spin complexes always have more magnetic moment than low spin complexes. On the other hand, `[Co(CN)_(6)]^(3-)` is referred to as low spin complex, because the electrons are arranged so that they remain paired as much as p[ossible. In this case, d-orbitals involved in hybridization scheme are from lower energy shell than ns and np-orbitals.