What is the coordination number and geometry of the complex compound (NH4)2[Fe(H2O)2Cl4]?

1 answer

In the complex compound \((\text{NH}_4)_2[\text{Fe}(\text{H}_2\text{O})_2\text{Cl}_4]\), the central metal ion is iron (Fe), and it is being coordinated by two water molecules (\(\text{H}_2\text{O}\)) and four chloride ions (\(\text{Cl}^-\)).

To determine the coordination number, we need to count the number of ligands that are directly bonded to the central metal ion (Fe). In this case:

  • There are 2 water molecules contributing 2 coordination sites.
  • There are 4 chloride ions contributing 4 coordination sites.

Therefore, the total coordination number is: \[ 2 (\text{from } \text{H}_2\text{O}) + 4 (\text{from } \text{Cl}^-) = 6 \]

The coordination number of this complex is 6.

In terms of geometry, a coordination number of 6 typically results in an octahedral geometry. Thus, the geometry of the complex \((\text{NH}_4)_2[\text{Fe}(\text{H}_2\text{O})_2\text{Cl}_4]\) is octahedral.

Summary:

  • Coordination number: 6
  • Geometry: Octahedral