Which of the following molecule/species are iso-structural with `N_(3)^(-)`ion ?

Options

A. `I_(3)^(+)`
B. `I_(3)^(-)`
C. `NH_(2)^(-)`
D. `HCO_(2)^(-)`

Answer

To determine which of the given species are iso-structural with the azide ion (N₃⁻), we need to analyze the structure and hybridization of each species.

### Step 1: Analyze the structure of the azide ion (N₃⁻)
- The azide ion consists of three nitrogen atoms connected in a linear arrangement.
- The Lewis structure shows that the central nitrogen is double-bonded to both terminal nitrogens.
- The hybridization of the nitrogen atoms in N₃⁻ is sp, leading to a linear shape.

### Step 2: Evaluate the options
1. **I₃⁺ (Triiodide ion)**
- The structure of I₃⁺ consists of three iodine atoms.
- The central iodine atom is bonded to two terminal iodine atoms and has two lone pairs.
- The hybridization is sp³, resulting in a bent shape, which is not linear.

2. **I₃⁻ (Triiodide ion)**
- The structure of I₃⁻ also consists of three iodine atoms.
- The central iodine atom is bonded to two terminal iodine atoms and has three lone pairs.
- The hybridization is sp³d, resulting in a linear shape, similar to N₃⁻.

3. **NH₂⁻ (Amide ion)**
- The structure of NH₂⁻ consists of one nitrogen atom bonded to two hydrogen atoms and has one lone pair.
- The hybridization is sp³, leading to a bent shape, which is not linear.

4. **HCO₂⁻ (Formate ion)**
- The structure of HCO₂⁻ consists of one carbon atom bonded to two oxygen atoms and one hydrogen atom.
- The hybridization of carbon is sp², resulting in a trigonal planar shape, which is not linear.

### Step 3: Conclusion
- The only species that is iso-structural with the azide ion (N₃⁻) is **I₃⁻** since both have a linear shape.

### Final Answer
The species that are iso-structural with N₃⁻ is **I₃⁻**.

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