Coordination Compounds - Result Question 52
####59. Which of the following complex compounds will exhibit highest paramagnetic behaviour?
[2011M]
(At. No. : $Ti=22, Cr=24, Co=27, Zn=30$ )
(a) $[Ti(NH_3)_6]^{3+}$
(b) $[Cr(NH_3)_6]^{3+}$
(c) $[Co(NH_3)_6]^{3+}$
(d) $[Zn(NH_3)_6]^{2+}$
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Solution:
- (b)
(a) $[Ti(NH_3)_6]^{3+}: 3 d^{1}$ configuration and thus has one unpaired electron.
(b) $[Cr(NH_3)_6]^{3+}$ : In this complex $Cr$ is in +3 oxidation state.
$Cr^{3+}: 3 d^{3} 4 s^{0}$
Thus, the complex is paramagnetic.
(c) $[Co(NH_3)_6]^{3+}$ : In this complex, cobalt ion is in +3 oxidation state with $3 d^{6}$ configuration.
$Co^{3+},[Ar] 3 d^{6}$
$[Co(NH_3)_6]^{3+}$
(inner orbital or $d^{2} s p^{3}$ hybrid orbital low spin complex) diamagnetic
(d) In this complex Zn exists as
$Zn^{2+}$ ion
$Zn^{2+}$ ion : $3 d^{10} 4 s^{0}$
$Zn^{2+}$ ion in $[Zn(NH_3)_4]^{2+}$
Due to presence of paired electrons, complex is diamagnetic in nature.
