Question

The correct IUPAC name of [Pt(NH$_3$)$_2$Cl$_2$] is:
A. diamminedichloridoplatinum (II)
B. diamminedichloridoplatinum (IV)
C. diamminedichloridoplatinum (0)
D. dichloridoammineplatinum (IV)

Answer 1

Hint: The given complex [Pt(NH$_3$)$_2$Cl$_2$] is a coordination compound, and a neutral complex. There are numerous steps followed to name these compounds. Always name the ligands in alphabetical order, and cation have to be written before the anion.

Complete step by step answer:
1. Let us name this compound step by step. Firstly, let us know the ligands present in this complex.
2. The ligands are ammonia (NH$_3$), and chloride. Here, ammonia is neutral ligand; so it will be written as ammine, whereas chloride is an anion, so it will be written as chloride (ide to –o).
3. In this complex there are two ammine ligands, so the greek prefix di- will be added before the ammine while naming the complex i.e. diammine.
4. Now, the central metal present in the complex is a cation, it is named the same as the element i.e. platinum.
5. We will calculate the oxidation state of platinum in the complex [Pt(NH$_3$)$_2$Cl$_2$], we know that charge of ammine ligand is 0, and the chlorine has -1 charge.
So, let us consider the oxidation state of platinum to be x; the oxidation state can be written as:
x + 2 (0) + 2(-1) = 0;
Here, we get x = 2, as the complex is neutral as mentioned.
Thus, in this complex we have the oxidation state of platinum is +2.

Now, we will write alphabetically, then it will be diamminechloridoplatinum (II).

Thus. The IUPAC name of [Pt(NH$_3$)$_2$Cl$_2$] is diamminechloridoplatinum (II).
The correct option is A.

Note: Don’t get confused if the central metal present in the complex is an anion, then the name of metal will end with the suffix –ate like Pt will be platinate. There is no need of confusion , just look at the complex, whether it is anion, cation, or neutral.