A complex cation is formed by Pt( in some oxidation state ) with ligands ( in proper number so that coordination number of Pt becomes six ). Which of the following can be its correct IUPAC name ?

Options

A. Diammineethylenediaminedithicocyanato-S-platinum (II) ion
B. Diammineethylenediaminedithicocyanato-S-platinate (IV) ion
C. Diammineethylenediaminedithicocyanato-S-platinum (IV) ion
D. Diamminebis (ethylenediamine ) dithiocyanate -S- platinum (IV) ion

Answer

To solve the question regarding the correct IUPAC name of a complex cation formed by platinum with ligands that give it a coordination number of six, we will follow these steps:

### Step-by-Step Solution:

1. **Identify the Coordination Number**:
The problem states that the coordination number of platinum (Pt) must be six. This means that the total number of ligand donor atoms attached to the platinum must equal six.

**Hint**: The coordination number is determined by the number of ligands and their denticity (how many donor atoms each ligand has).

2. **Determine the Oxidation State of Platinum**:
The oxidation state of platinum can vary, and we need to analyze the ligands and their charges to determine the oxidation state in each option provided.

**Hint**: The charge of the complex cation can be calculated by considering the oxidation state of the metal and the charges of the ligands.

3. **Analyze Each Option**:
- **Option 1**: "diamine, thiocyanato, platinum(II)" - Here, platinum is in the +2 oxidation state. The total charge of the complex would be neutral, which does not fit the requirement of being a cation.

- **Option 2**: "diamine, ethylene diamine, thiocyanato platinum(IV)" - Platinum is in the +4 oxidation state. The charge calculation shows a +2 charge, which is a cation.

- **Option 3**: "diamine, ethylene diamine, thiocyanato platinum(III)" - Platinum is in the +3 oxidation state. The charge calculation shows a +1 charge, which is also a cation.

- **Option 4**: "diamine, bis(ethylene diamine), thiocyanato platinum(IV)" - This option results in a coordination number of 8, which exceeds the required coordination number of 6.

**Hint**: Carefully check the oxidation states and ensure that the total charge matches the requirement for a cation.

4. **Conclusion**:
Since both options 2 and 3 yield complex cations, but the term "complex cation" typically refers to a +1 charge unless specified otherwise, option 3 is the most appropriate answer.

**Hint**: In naming coordination compounds, the overall charge of the complex is crucial in determining the correct nomenclature.

### Final Answer:
The most appropriate IUPAC name for the complex cation is "diamine ethylene diamine thiocyanato platinum(III)".