JEE Main201910 Jan 2019Evening ShiftChemistrySolid StateActual
A compound of formula A 2 B 3 has the HCP lattice. Which atom forms the HCP lattice and what fraction of the tetrahedral voids are occupied by the other atoms?
Options
- AHCP lattice - B 2 3 tetrahedral voids - A
- BHCP lattice - A 1 3 tetrahedral voids - B
- CHCP lattice - B 1 3 tetrahedral voids - A
- DHCP lattice - A 2 3 tetrahedral voids - B
Correct answer
C. HCP lattice - B 1 3 tetrahedral voids - A
Step-by-step solution
Atom B forms HCP as anions are larger in size. From the formula A 2 B 3 , Number of B atoms = 3 , Then, number of tetrahedral voids = 2 × Tetrahedral voids = 2 × 3 = 6 . As ' A ' is occupying tetrahedral voids, 1 3 of tetrahedral voids = 1 3 × 6 = 2 Therefore, formula of the compound = A 2 B 3