Which of the following molecules or ions is not linear?

Options

A. `BeCl_(2)`
B. `I_(3)^(-)`
C. `CS_(2)`
D. `I Cl_(2)^(+)`

Explanation

To determine which of the given molecules or ions is not linear, we will analyze each option one by one based on their molecular geometry and hybridization.

### Step 1: Analyze BeCl2
- **Molecule:** BeCl2
- **Valence Electrons:** Beryllium (Be) has 2 valence electrons, and each chlorine (Cl) has 7 valence electrons.
- **Covalency:** Beryllium can form 2 sigma bonds with the two chlorine atoms.
- **Hybridization:**
- Steric Number = Number of Sigma Bonds + Number of Lone Pairs = 2 + 0 = 2
- Hybridization = sp
- **Geometry:** The geometry for sp hybridization is linear.

### Step 2: Analyze I3-
- **Molecule:** I3-
- **Valence Electrons:** Iodine (I) has 7 valence electrons. For I3-, we have 3 iodine atoms and an extra electron due to the negative charge.
- **Covalency:** Total covalency = 7 (maximum) + 1 (extra electron) = 8. With 2 bonds formed, there are 2 lone pairs remaining.
- **Hybridization:**
- Steric Number = 2 (sigma bonds) + 2 (lone pairs) = 4
- Hybridization = sp3
- **Geometry:** With 3 lone pairs, the shape is linear (as per VSEPR theory).

### Step 3: Analyze CS2
- **Molecule:** CS2
- **Valence Electrons:** Carbon (C) has 4 valence electrons, and each sulfur (S) has 6 valence electrons.
- **Covalency:** Carbon forms double bonds with both sulfur atoms, completing its covalency.
- **Hybridization:**
- Steric Number = 2 (double bonds count as 1 sigma bond each) + 0 (lone pairs) = 2
- Hybridization = sp
- **Geometry:** The geometry for sp hybridization is linear.

### Step 4: Analyze ICl2+
- **Molecule:** ICl2+
- **Valence Electrons:** Iodine has 7 valence electrons, and each chlorine has 7. The positive charge indicates that one electron is removed.
- **Covalency:** Total covalency = 7 - 1 (due to positive charge) = 6. With 2 bonds formed, there are 2 lone pairs remaining.
- **Hybridization:**
- Steric Number = 2 (sigma bonds) + 2 (lone pairs) = 4
- Hybridization = sp3
- **Geometry:** With 2 lone pairs, the shape is bent (similar to H2O).

### Conclusion
From the analysis:
- BeCl2: Linear
- I3-: Linear
- CS2: Linear
- ICl2+: **Not Linear (Bent Shape)**

Thus, the molecule that is not linear is **ICl2+**.

### Final Answer:
**ICl2+ is not linear.**