A crystalline solid has a cubic structure in which tungsten (W) atoms are located at the cube corners of the unit cell, oxygen atoms at the cube edges and sodium atom at the cube centre. The molecular formula of the compund is

Options

A. `Na_(2)WO_(3)`
B. `NaWO_(4)`
C. `NaWO_(3)`
D. `Na_(2)WO_(4)`

Explanation

To determine the molecular formula of the compound based on the given cubic structure, we will analyze the contributions of each type of atom present in the unit cell.

### Step-by-Step Solution:

1. **Identify the Atoms and Their Positions**:
- Tungsten (W) atoms are located at the **corners** of the cube.
- Oxygen (O) atoms are located at the **edges** of the cube.
- Sodium (Na) atoms are located at the **center** of the cube.

2. **Calculate the Contribution of Tungsten (W)**:
- There are **8 corners** in a cube.
- Each corner atom contributes **1/8** of an atom to the unit cell.
- Therefore, the total contribution from tungsten is:
\[ \text{Total W} = 8 \times \frac{1}{8} = 1 \text{ W atom} \]

3. **Calculate the Contribution of Oxygen (O)**:
- There are **12 edges** in a cube.
- Each edge atom contributes **1/4** of an atom to the unit cell.
- Therefore, the total contribution from oxygen is:
\[ \text{Total O} = 12 \times \frac{1}{4} = 3 \text{ O atoms} \]

4. **Calculate the Contribution of Sodium (Na)**:
- There is **1 sodium atom** located at the center of the cube.
- Therefore, the total contribution from sodium is:
\[ \text{Total Na} = 1 \text{ Na atom} \]

5. **Combine the Contributions**:
- Now, we can combine the contributions of each type of atom to write the molecular formula:
- Sodium (Na): 1
- Tungsten (W): 1
- Oxygen (O): 3
- Hence, the molecular formula of the compound is:
\[ \text{NaW O}_3 \]

### Final Answer:
The molecular formula of the compound is **NaWO₃**.