The IUPAC name of `[Co(NH_3)_6[Cr(C_2O_4)_3]` is

Options

A. Hexa-ammine cobalt (III) tris (Oxalato) chromium
B. Hexa-ammine cobalt (III) tris (Oxalato) chromate (III)
C. Hexa-ammine cobalt tris (Oxalato) chromium (III)
D. Hexa-ammine cobalt (III) chromium (III) oxalate

Explanation

To determine the IUPAC name of the coordination compound \([Co(NH_3)_6][Cr(C_2O_4)_3]\), we can follow these steps:

### Step 1: Identify the Components
The compound consists of two parts: a cationic part \([Co(NH_3)_6]^{3+}\) and an anionic part \([Cr(C_2O_4)_3]^{3-}\).

### Step 2: Name the Cationic Part
- The cationic part is \([Co(NH_3)_6]^{3+}\).
- The ligand \(NH_3\) is called "ammine".
- Since there are six ammine ligands, we use the prefix "hexa".
- Therefore, the name for the cationic part is "hexaamminecobalt(III)".

### Step 3: Name the Anionic Part
- The anionic part is \([Cr(C_2O_4)_3]^{3-}\).
- The ligand \(C_2O_4^{2-}\) is called "oxalate", and since there are three oxalate ligands, we use the prefix "tris".
- The metal is chromium, and since it is part of an anionic complex, we use the suffix "chromate".
- The oxidation state of chromium in this complex is +3, so we denote it as "chromate(III)".

### Step 4: Combine the Names
- The full name of the coordination compound is formed by combining the names of the cation and anion.
- Since the cation is named first, we write: "hexaamminecobalt(III) tris(oxalato)chromate(III)".

### Final Answer
The IUPAC name of the compound \([Co(NH_3)_6][Cr(C_2O_4)_3]\) is:
**hexaamminecobalt(III) tris(oxalato)chromate(III)**.

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