Question

Which of the following is a high spin complex?

• A. [Co(NH3)6]3+
• B. [Fe(CN)6]4–
• C. [Ni(CN)4]2–
• D. [FeF6]3–

Answer 1

Answer: (D)

$FeF6$3–

Answer 2

The complex [fef6]4– is paramagnetic and uses outer orbital (4d) in hybridisation (sp3d2) ; it is thus called as outer orbital or high spin or spin free complex. so :

Fe2+, [Ar]3d6

[FeF6]4–

sp3d2 hybrid orbitals

Six pairs of electrons from six f**– ions.**