Which of the following species is non-linear ?

Options

A. `ICI_(2)^(-)`
B. `I_(3)^(-)`
C. `N_(3)^(-)`
D. `CIO_(2)^(-)`

Explanation

To determine which of the given species is non-linear, we can analyze the molecular geometry of each species based on their Lewis structures and steric numbers. Here’s a step-by-step solution:

### Step 1: Identify the species
We need to analyze the following species:
1. ICl2^-
2. I3^-
3. CLO2^-
4. N2

### Step 2: Draw the Lewis structures and calculate the steric numbers

#### For ICl2^-
- **Valence Electrons Calculation**: Iodine (I) has 7 valence electrons, and each chlorine (Cl) has 7. For ICl2^-, we have:
- I: 7
- Cl: 2 × 7 = 14
- Total = 7 + 14 + 1 (for the negative charge) = 22 valence electrons.

- **Lewis Structure**: Iodine is the central atom. It forms two bonds with chlorine and has three lone pairs.

- **Steric Number**: The steric number is the number of bonded atoms plus lone pairs. Here, steric number = 2 (bonded Cl) + 3 (lone pairs) = 5.

- **Geometry**: With a steric number of 5, the molecular geometry is trigonal bipyramidal, but the presence of three lone pairs leads to a non-linear shape (T-shaped).

#### For I3^-
- **Valence Electrons Calculation**: Each iodine has 7 valence electrons. For I3^-, we have:
- I: 3 × 7 = 21
- Total = 21 + 1 (for the negative charge) = 22 valence electrons.

- **Lewis Structure**: One iodine is central, bonded to two others, with three lone pairs on the central iodine.

- **Steric Number**: Steric number = 2 (bonded I) + 3 (lone pairs) = 5.

- **Geometry**: The structure is also non-linear (T-shaped).

#### For CLO2^-
- **Valence Electrons Calculation**: Chlorine has 7 valence electrons, and each oxygen has 6. For CLO2^-, we have:
- Cl: 7
- O: 2 × 6 = 12
- Total = 7 + 12 + 1 (for the negative charge) = 20 valence electrons.

- **Lewis Structure**: Chlorine is the central atom, forms a double bond with one oxygen and a single bond with the other, leading to two lone pairs on chlorine.

- **Steric Number**: Steric number = 2 (bonded O) + 2 (lone pairs) = 4.

- **Geometry**: With a steric number of 4, the molecular geometry is bent (non-linear).

#### For N2
- **Valence Electrons Calculation**: Each nitrogen has 5 valence electrons. For N2, we have:
- N: 2 × 5 = 10.

- **Lewis Structure**: N2 has a triple bond between the two nitrogen atoms with no lone pairs.

- **Steric Number**: Steric number = 3 (triple bond) + 0 (lone pairs) = 3.

- **Geometry**: The geometry is linear.

### Step 3: Conclusion
From the analysis:
- ICl2^- is non-linear (T-shaped).
- I3^- is non-linear (T-shaped).
- CLO2^- is non-linear (bent).
- N2 is linear.

**Final Answer**: The non-linear species are ICl2^-, I3^-, and CLO2^-.