question_answer

The magnetic moment of the complex anion \[{{[Cr(NO)(N{{H}_{3}}){{(CN)}_{4}}]}^{2-}}\] is:

A) 5.91 BM           

B) 3.87 BM

C) 1.73 BM           

D) 2.82 BM

Correct Answer: D

Solution :

[d] In \[{{[Cr\left( NO \right)\left( N{{H}_{3}} \right){{\left( CN \right)}_{4}}]}^{2-}},\] \[C{{r}^{2+}}({{d}^{4}})\] is given as:  i.e., 2 unpaired electrons \[\mu =\sqrt{2(2+2)}=\sqrt{8}=2.82\,BM\]