Right option for the number of tetrahedral and octahedral voids in hexagonal primitive unit cell are :

1. 8, 4

2. 6, 12

3. 2, 1

4. 12, 6

Doubtly Asked 30 Oct 2026 NEET UG 2021 neet Save WhatsApp Report

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Answer: 4. 12, 6

Key idea: in a close-packed structure with \(n\) atoms per cell, there are \(n\) octahedral voids and \(2n\) tetrahedral voids.

A hexagonal primitive unit cell (hcp) contains 6 atoms. So octahedral voids = 6 and tetrahedral voids = 12, i.e. (12, 6) in the order given.

Doubtly AI · 30 Oct 2026 AI-generated · not yet verified Report

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