AP EAMCET20228 Jul 2022Evening ShiftChemistrySolid StateActual
In a crystal lattice, anions A forms hcp array, 2 / 3 of the tetrahedral voids are occupied by cations C . What is the formula of crystal?
Options
- AC₃ A₄
- BC ₄ ~A ₃
- CC₂ A₃
- DC₃ A₂
Correct answer
B. C ₄ ~A ₃
Step-by-step solution
For hexagonal close packed ( h c p) crystal, there are 6 atoms per unit cell. That means anion A= number of octahedral voids = number of atoms per unit cell =6 . We also know that, tetrahedral voids =2 octahedral voids . C= 2 3 (2 6)=8 Hence, C: A=8: 6=4: 3 Therefore, the formula of the crystal is C₄ A₃ .