The name of the compound `[Co(NH_(3))_(5) NO_2]Cl_2` will be

Options

A. pentaamminonitrocobalt (II) chloride
B. pentamminenitrochloridecobalt(III) chloride
C. pentanitrosoamminechlorocobaltate(III) .
D. pentaamminenitrocobalt(III) chloride

Answer

To name the compound \([Co(NH_3)_5NO_2]Cl_2\), we can follow these steps:

### Step 1: Identify the Cation and Anion
The compound consists of a cationic complex \([Co(NH_3)_5NO_2]^+\) and two chloride ions \((Cl^−)\) as the anions.

### Step 2: Name the Ligands
- The ligands in the cationic part are:
- \(NH_3\) (ammine) which is a neutral ligand.
- \(NO_2\) (nitro) which is a negatively charged ligand.

### Step 3: Count the Ligands
- There are 5 \(NH_3\) ligands, which will be named as "pentaammine".
- There is 1 \(NO_2\) ligand, which will be named as "nitro".

### Step 4: Name the Metal and Determine its Oxidation State
- The metal in the complex is cobalt (Co).
- To find the oxidation state of cobalt, we consider the charges:
- Each \(NH_3\) is neutral (0 charge).
- \(NO_2\) has a charge of -1.
- The two chloride ions contribute a total charge of -2.

Thus, the overall charge of the complex \([Co(NH_3)_5NO_2]^+\) must be +2 to balance the -2 from the chlorides. Therefore, cobalt must have an oxidation state of +3.

### Step 5: Combine the Names
- The name of the cationic part is "pentaammine nitro cobalt(III)".
- The anionic part is "chloride" (since we have two chloride ions, we simply use "chloride" in the name).

### Step 6: Write the Full Name
Putting it all together, the full name of the compound is:
**Pentaammine nitro cobalt(III) chloride**.

### Final Answer
The name of the compound \([Co(NH_3)_5NO_2]Cl_2\) is **Pentaammine nitro cobalt(III) chloride**.

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