The correct IUPAC name of `[Cr(H_2O)_(5)(NCS)][ZnBr_4]` is

Options

A. pentaaqua isothiocyanato chromate (II) tetra bromozincate (II)
B. pentaaqua isothio cyanate zince bromide chromate (III)
C. pentaaque isothiocyanato chromium (III) tetra bromozincate (II)
D. isothio cyantopenta aqua ammine chromium (II) zinc chloride (IV)

Answer

To determine the correct IUPAC name for the complex `[Cr(H2O)5(NCS)][ZnBr4]`, we will follow these steps:

### Step 1: Identify the Components of the Complex
The complex consists of two parts:
- The cation: `[Cr(H2O)5(NCS)]`
- The anion: `[ZnBr4]`

### Step 2: Determine the Ligands
- The ligands in the cation are:
- 5 water molecules (H2O), which are called "aqua."
- 1 isothiocyanate ion (NCS), which is called "isothiocyanato."

### Step 3: Count the Ligands
- There are 5 aqua ligands, which is denoted as "penta."
- There is 1 isothiocyanate ligand.

### Step 4: Determine the Oxidation States
- The oxidation state of zinc (Zn) in `[ZnBr4]` is +2, as it is a common oxidation state for zinc.
- Each bromide ion (Br) has a charge of -1, and with 4 bromide ions, the total charge from bromides is -4.
- Therefore, the overall charge of the anion `[ZnBr4]` is -2.
- For the cation `[Cr(H2O)5(NCS)]`, to balance the overall charge of the complex, chromium (Cr) must be in the +3 oxidation state.

### Step 5: Write the Name of the Cation
- The name of the cation is constructed as follows:
- Ligands are named in alphabetical order regardless of their quantity.
- "Penta" comes before "isothiocyanato."
- Therefore, the cation is named "penta-aqua isothiocyanato chromium(III)."

### Step 6: Write the Name of the Anion
- The anion is `[ZnBr4]`, which is named "tetra-bromo zincate."
- The term "zincate" is used when zinc is in a complex ion.

### Step 7: Combine the Names
- The full name of the complex is:
- "Penta-aqua isothiocyanato chromium(III) tetra-bromo zincate."

### Final Answer
The correct IUPAC name of `[Cr(H2O)5(NCS)][ZnBr4]` is:
**Penta-aqua isothiocyanato chromium(III) tetra-bromo zincate.**

---