The empty space left in hcp packing is :

Options

A. `26%`
B. `74%`
C. `52.4%`
D. `80%`

Answer

To find the empty space left in hexagonal close packing (hcp), we can follow these steps:

### Step-by-Step Solution:

1. **Understand Packing Fraction**:
- The packing fraction is defined as the fraction of volume in a crystal structure that is occupied by the atoms. It is expressed as a percentage.

2. **Know the Packing Fraction for HCP**:
- The packing fraction for hexagonal close packing (hcp) is known to be 74%. This means that 74% of the volume is occupied by the atoms.

3. **Calculate the Empty Space**:
- To find the empty space, we subtract the packing fraction from 100%.
- Formula:
\[ \text{Empty Space} = 100\% - \text{Packing Fraction} \]
- Substituting the known value:
\[ \text{Empty Space} = 100\% - 74\% = 26\% \]

4. **Conclusion**:
- Therefore, the empty space left in hcp packing is 26%.

### Final Answer:
The empty space left in hcp packing is **26%**.

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