A cubic solid is made up of two elements A and B. Atoms B are at the corners of the cube and A at the body centre. What is the formula of compound.

Answer

To find the formula of the compound formed by elements A and B in a cubic solid, we can follow these steps:

### Step 1: Identify the positions of the atoms
- Atoms of element B are located at the corners of the cube.
- Atoms of element A are located at the body center of the cube.

### Step 2: Count the number of atoms of element B
- A cube has 8 corners.
- Each corner atom contributes \( \frac{1}{8} \) of an atom to the unit cell.
- Therefore, the total contribution of B atoms is:
\[ \text{Total contribution from B} = 8 \times \frac{1}{8} = 1 \]

### Step 3: Count the number of atoms of element A
- There is 1 atom of A located at the body center.
- The contribution of this atom is:
\[ \text{Total contribution from A} = 1 \]

### Step 4: Write the formula based on the contributions
- From the contributions, we have:
- Total A = 1
- Total B = 1
- Therefore, the formula of the compound can be expressed as:
\[ \text{Formula} = A^1 B^1 = AB \]

### Final Answer
The formula of the compound is \( AB \).

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