[Ag(NH3)2]+ is a colorless complex ion right?
In solution, yes. I've never seen the ion any other way.
To determine the color of a complex ion like [Ag(NH3)2]+, we need to consider a few factors.
First, we need to know the coordination number of the central metal ion. In this case, the coordination number of silver (Ag) is 2 since there are two ammonia (NH3) molecules coordinated around it.
Next, we need to consider the ligands' nature. In this complex, ammonia (NH3) acts as a ligand, which is a molecule or ion that donates electron pairs to form a coordinate bond with the central metal ion. Ammonia is a weak field ligand, which means it does not significantly split the d-orbitals of the central metal ion.
Based on these factors, we can conclude that [Ag(NH3)2]+ is indeed a colorless complex ion. Weak field ligands typically do not cause significant d-orbital splitting, which means there are no energy level transitions that correspond to absorption of visible light. As a result, the complex appears colorless.