Question

Which of the following statements is NOT correct regarding voids in lattice structure?

• A. Four spheres are involved in the formation of a tetrahedral void.
• B. The octahedral void is surrounded by six spheres.
• C. There are two tetrahedral voids associated with each atom.
• D. There is one octahedral void associated with two atoms.

Hint:

Remember the ratio: Atoms ($N$) : Octahedral ($N$) : Tetrahedral ($2N$).

Answer 1

The Correct Option is D

Step 1: Concept In close-packed structures (ccp/hcp), the number of voids is mathematically related to the number of constituent atoms ($N$).

Step 2: Meaning For $N$ atoms, there are $2N$ tetrahedral voids and $N$ octahedral voids.

Step 3: Analysis (A) and (B) describe the coordination geometry correctly. (C) is correct as $2N/N = 2$. (D) is incorrect because there is 1 octahedral void per 1 atom ($N/N = 1$), not per 2 atoms.

Step 4: Conclusion Statement (D) contradicts the established ratio of octahedral voids to atoms. Final Answer: (D)