In which of the following species the bonds are non-directonal ?

Options

A. `NCl_(3)`
B. `RbCl`
C. `BeCl_(2)`
D. `BCl_(3)`

Answer

To determine which of the following species has non-directional bonds, we need to analyze the bonding nature of each species mentioned. Non-directional bonds are typically found in ionic compounds, while covalent bonds tend to be directional due to the overlap of atomic orbitals.

### Step-by-Step Solution:

1. **Identify the Species**: The species we need to analyze are \( \text{NCl}_3 \), \( \text{RbCl} \), \( \text{BeCl}_2 \), and \( \text{BCl}_3 \).

2. **Analyze \( \text{NCl}_3 \)**:
- \( \text{NCl}_3 \) (Nitrogen trichloride) has covalent bonds.
- The nitrogen atom forms three bonds with chlorine atoms, and due to the difference in electronegativity, the bonds are polar.
- The presence of a lone pair on nitrogen creates a dipole moment, indicating that the bonds are directional.

3. **Analyze \( \text{RbCl} \)**:
- \( \text{RbCl} \) (Rubidium chloride) is an ionic compound.
- It consists of \( \text{Rb}^+ \) and \( \text{Cl}^- \) ions.
- Ionic bonds do not involve the overlap of orbitals, and thus, they are considered non-directional.

4. **Analyze \( \text{BeCl}_2 \)**:
- \( \text{BeCl}_2 \) (Beryllium chloride) has covalent bonds.
- The beryllium atom forms bonds with two chlorine atoms, and due to the difference in electronegativity, the bonds are polar.
- The geometry of \( \text{BeCl}_2 \) is linear, but the bonds are still directional due to the nature of covalent bonding.

5. **Analyze \( \text{BCl}_3 \)**:
- \( \text{BCl}_3 \) (Boron trichloride) also has covalent bonds.
- Boron forms three bonds with chlorine atoms, and the geometry is trigonal planar.
- The bonds are polar, indicating that they are directional.

6. **Conclusion**:
- Among the species analyzed, only \( \text{RbCl} \) has non-directional bonds due to its ionic nature.

### Final Answer:
The species with non-directional bonds is \( \text{RbCl} \).