Question

What are the respective central-metal oxidation state, coordination number, and overall charge on the complex ion in Na2[Cr(NH3)2 (NCS)4]?

Answer 1

Answer:

Central-metal oxidation state: +2

Coordination number: 6

Overall charge: -2

Explanation:

In the ion complex:

Na₂[Cr(NH₃)₂(NCS)₄]

The central-metal is Cr, the ligands are NH₃ and NCS.

The NH₃ is a neutral ligand, while NCS is an anionic ligand with -1 in charge.

The overall charge of the complex is:

2Na⁺ +  [Cr(NH₃)₂(NCS)₄]⁻² → -2

As NCS gives -1 in charge and there are four NCS, The Cr must be in +2 of oxidation state to give an overall charge of -2.

As Cr is bonded to 2 NH₃ and 4 NCS, the coordination number is 2+4 = 6

I hope it helps!