Question

In the coordination compound (NH4)2[Fe(OH2)F5], the Fe is octahedrally coordinated. (a) Based on the fact that F is a weak-field ligand, pre- dict whether this compound is diamagnetic or para- magnetic. If it is paramagnetic, tell how many unpaired electrons it has. (b) By comparison with other complexes reviewed in this chapter, discuss the likely color of this compound. (c) Determine the d-electron configuration of the iron in this compound. (d) Name this compound.

Answer 1

Answer:The compound is paramagnetic. It has four unpaired electrons b) the compound will be green in colour. Ammonium pentaflourido aqua Iron II. Iron has a d-electron configuration of d4

Explanation: Weak field ligands cause weak crystal field splitting leading to the formation of paramagnetic species. Most iron II compounds appear green in colour. In naming ligands, negative ions are named first followed by neutral species. Iron has an outermost electron configuration of 3d4s2 so Fe II is a d4 ion