Name the `K[PtCl_(3)(eta^(2)-C_(2)H_(4))]` compound.

Answer

To name the coordination compound \( K[PtCl_3(η^2-C_2H_4)] \), we will follow these steps:

### Step 1: Identify the Counter Ion
The compound contains a potassium ion \( K^+ \) outside the coordination sphere. This will be named first in the compound's name.

**Hint:** The counter ion is always named first in coordination compounds.

### Step 2: Determine the Ligands
Inside the coordination sphere, we have three chloride ions \( Cl^- \) and one ethylene ligand \( C_2H_4 \). The ethylene ligand is denoted as \( η^2-C_2H_4 \), indicating that it is a bidentate ligand (it forms two bonds with the metal).

**Hint:** Count the number of each type of ligand and remember to use the appropriate prefixes (mono-, di-, tri-, etc.) for naming.

### Step 3: Name the Ligands
- For the three chloride ions, we use the prefix "tri" and name it as "trichlorido".
- The ethylene ligand is named as "ethylene".

**Hint:** When naming ligands, use the alphabetical order regardless of the number of ligands.

### Step 4: Identify the Central Metal and its Oxidation State
The central metal atom is platinum (Pt). From the compound, we can determine the oxidation state of platinum. The overall charge of the coordination complex is neutral, and since potassium has a +1 charge, the charge of the coordination sphere must be -1. The three chloride ions contribute -3, and the ethylene is neutral. Therefore, the oxidation state of platinum must be +2.

**Hint:** To find the oxidation state of the central metal, consider the charges contributed by the ligands and the overall charge of the complex.

### Step 5: Combine the Names
Now we can combine all the parts:
1. Counter ion: potassium
2. Ligands: trichlorido and ethylene
3. Central metal: platinum with oxidation state +2, which is indicated by the suffix "ate".

Putting it all together, the name of the compound is:
**Potassium trichlorido(η^2-ethylene)platinate(II)**

### Final Answer
**Potassium trichlorido(η^2-ethylene)platinate(II)**