Q. Which of the following is diamagnetic ?

 4634  175 JEE MainJEE Main 2013Coordination Compounds Report Error

Solution:

has magnetic moment of a single unpaired electron whereas has a magnetic moment of five unpaired electrons. is paramagnetic with four unpaired electrons while is diamagnetic. This anomaly is explained by valence bond theory in terms of formation of inner and outer orbital coordination entities. is an inner orbital complexes having hybridization.