Which among the following metals crystallises as a simple cube ?

Options

A. Polonium
B. Iron
C. Copper
D. Gold

Answer

To determine which among the given metals crystallizes as a simple cube, we need to analyze the crystal structures of each metal mentioned in the options: Polonium, Iron, Copper, and Gold.

### Step-by-Step Solution:

1. **Understanding Simple Cubic Structure**:
- A simple cubic structure is characterized by atoms located only at the corners of the cube. Each corner atom contributes 1/8th of an atom to the unit cell, resulting in a total of 1 atom per unit cell.

2. **Analyzing Each Metal**:
- **Polonium (Po)**: Polonium crystallizes in a simple cubic structure.
- **Iron (Fe)**: Iron has different allotropes. At high temperatures, it crystallizes in a face-centered cubic (FCC) structure, and at lower temperatures, it adopts a body-centered cubic (BCC) structure. Therefore, it does not crystallize in a simple cubic structure.
- **Copper (Cu)**: Copper crystallizes in a face-centered cubic (FCC) structure, not a simple cubic structure.
- **Gold (Au)**: Gold also crystallizes in a face-centered cubic (FCC) structure, not a simple cubic structure.

3. **Conclusion**:
- Among the options provided, Polonium is the only metal that crystallizes in a simple cubic structure.

### Final Answer:
**Polonium (Po)** crystallizes as a simple cube.

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