The IUPAC name of `[Co (NH_(3))_(5)ONO]^(2+)` ion is

Options

A. pentamminenitrito cobalt (IV ) ion
B. pentamminenitro cobalt (III ) ion
C. pentamminenitrito cobalt (III ) ion
D. pentamminenitro cobalt (IV ) ion

Explanation

To determine the IUPAC name of the complex ion `[Co(NH₃)₅ONO]²⁺`, we can follow these steps:

### Step 1: Identify the Central Metal Ion
The central metal ion in the complex is cobalt (Co).

### Step 2: Identify the Ligands
The ligands attached to the cobalt ion are:
- 5 ammonia (NH₃) molecules, which are neutral ligands.
- 1 nitrito (ONO) ligand, which is an ambidentate ligand. In this case, it is connected through the oxygen atom (ONO), so we refer to it as "nitrito".

### Step 3: Determine the Oxidation State of the Metal
To find the oxidation state of cobalt in the complex:
- The ammonia ligands contribute 0 to the oxidation state (since they are neutral).
- The nitrito ligand contributes -1 to the oxidation state.

Let the oxidation state of cobalt be \( x \). The overall charge of the complex is +2.

The equation will be:
\[ x + 5(0) + (-1) = +2 \]
\[ x - 1 = 2 \]
\[ x = 3 \]

Thus, the oxidation state of cobalt is +3.

### Step 4: Naming the Ligands
According to IUPAC nomenclature:
- The ligands are named in alphabetical order, regardless of the number of each type.
- "Penta" is used for 5 ammonia ligands, and "nitrito" is used for the nitrito ligand.

So, the ligands will be named as:
- Pentaammine (for 5 NH₃)
- Nitrito (for ONO)

### Step 5: Combine the Names
The name of the complex will start with the names of the ligands followed by the name of the metal and its oxidation state in Roman numerals.

Thus, we write:
- Ligands: Pentaammine, Nitrito
- Metal: Cobalt
- Oxidation State: III (for +3)

### Final Name
Putting it all together, the IUPAC name of the complex `[Co(NH₃)₅ONO]²⁺` is:
**Pentaammine nitrito cobalt(III)**