question_answer

Which of the following complex compound (s) is/are paramagnetic and low spin?

(I) \[{{K}_{3}}\left[ Fe\left( C{{N}_{6}} \right) \right]\]

(II) \[{{\left[ Ni{{\left( CO \right)}_{4}} \right]}^{10}}\]

(III) \[{{\left[ Cr{{(N{{H}_{3}})}_{6}} \right]}^{3+}}\]

(IV) \[{{\left[ Mn\,(C{{N}_{6}}) \right]}^{4\,-}}\]

Choose the correct code:

A) I only                           

B) II and III

C) I and IV            

D) IV only

Correct Answer: C

Solution :

[c] \[F{{e}^{3+}}\,in\,{{\left[ Fe(C{{N}_{6}}) \right]}^{3-}}\] \[\Rightarrow \] low spin complex \[\mu =1.732BM\] Ni in \[\left[ Ni{{\left( CO \right)}_{4}} \right]\] \[C{{r}^{3+}}\,in{{[Cr{{\left( N{{H}_{3}} \right)}_{6}}]}^{3+}}\] \[\Rightarrow \] low and high spin complex is applicable for \[{{d}^{4}}\] to \[{{d}^{7}}\] configuration \[M{{n}^{2+}}in{{\left[ Mn{{\left( CN \right)}_{6}} \right]}^{4-}}\] \[\Rightarrow \] low spin complex \[\mu =1.732\,BM\]