Which of the following crystals are not covalent ?

Options

A. `CO_(2)`
B. `SiO_(2)`
C. BaO
D. `CsNO_(3)`

Answer

To solve the question of which of the following crystals are not covalent, we will analyze each crystal type mentioned in the question.

### Step-by-Step Solution:

1. **Identify the Crystals**:
We need to determine the nature of the given crystals. The crystals mentioned are:
- Carbon Dioxide (CO2)
- Silicon Dioxide (SiO2)
- Barium Oxide (BaO)
- Cesium Nitrate (CsNO3)

2. **Analyze Carbon Dioxide (CO2)**:
- Carbon dioxide is a molecular solid. It consists of discrete molecules held together by van der Waals forces (London dispersion forces).
- **Conclusion**: CO2 is **not** a covalent or network solid.

3. **Analyze Silicon Dioxide (SiO2)**:
- Silicon dioxide, commonly known as quartz, is a covalent or network solid. It has a three-dimensional structure where each silicon atom is covalently bonded to four oxygen atoms.
- **Conclusion**: SiO2 **is** a covalent or network solid.

4. **Analyze Barium Oxide (BaO)**:
- Barium oxide is an ionic compound. It consists of barium ions (Ba²⁺) and oxide ions (O²⁻) held together by ionic bonds.
- **Conclusion**: BaO is **not** a covalent solid.

5. **Analyze Cesium Nitrate (CsNO3)**:
- Cesium nitrate is also an ionic compound. It consists of cesium ions (Cs⁺) and nitrate ions (NO3⁻) held together by ionic bonds.
- **Conclusion**: CsNO3 is **not** a covalent solid.

6. **Final Conclusion**:
- The crystals that are **not covalent** are:
- Carbon Dioxide (CO2)
- Barium Oxide (BaO)
- Cesium Nitrate (CsNO3)

### Answer:
The crystals that are not covalent are **Carbon Dioxide (CO2), Barium Oxide (BaO), and Cesium Nitrate (CsNO3)**.