What is the IUPAC name of `Hg[Co(SCN)_(4)]`?

Options

A. Mercury(II) tetrathiocynato-S-cobaltate(II)
B. Mercury(I) tetrathiocyanato-S-cobaltate(II)
C. mercury(II) tetrathiocyanato-N-cobaltate(II)
D. mercury(II) tetrathiocyanato-S-cobalt(II)

Answer

To find the IUPAC name of the complex `Hg[Co(SCN)_(4)]`, we can follow these steps:

### Step 1: Identify the components of the complex
The complex consists of mercury (Hg) and cobalt (Co) with four thiocyanate (SCN) ligands.

### Step 2: Determine the oxidation states
- Mercury (Hg) is in the +2 oxidation state in this complex.
- Cobalt (Co) is also in the +2 oxidation state as it is coordinated with four thiocyanate ligands.

### Step 3: Naming the ligands
The ligand SCN is called thiocyanate. Since it is a bidentate ligand, we need to specify the donor atom. In this case, the sulfur (S) atom is the donor atom. Therefore, we will name it as thiocyanato-S.

### Step 4: Count the number of ligands
There are four thiocyanate ligands. In nomenclature, we use prefixes to indicate the number of ligands:
- 1 = mono
- 2 = di
- 3 = tri
- 4 = tetra
Thus, we will use "tetra" for four thiocyanate ligands.

### Step 5: Name the cation
The cation in this complex is cobalt, which will be named as cobaltate when it is part of a coordination complex.

### Step 6: Combine the names
Putting it all together, we first write the name of the ligands followed by the name of the cation:
- Ligands: tetra thiocyanato-S
- Cation: cobaltate

### Step 7: Finalize the name
Since cobalt is in the +2 oxidation state, we denote this in the name. Therefore, the final IUPAC name of the complex is:
**Mercury(II) tetra thiocyanato-S cobaltate(II)**.

### Summary of the IUPAC Name
The IUPAC name of `Hg[Co(SCN)_(4)]` is **Mercury(II) tetra thiocyanato-S cobaltate(II)**.

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