Q. The correct statement in the following is
A) The ionic crystal of $AgBr$ has Schottky defect
B) The coordination number of $Na^{+}$ ion in NaCl is 4
C) In ionic compounds having Frenkel defect, the ratio $\frac{r_{+}}{r_{-}}$ is high
D) The unit cell having crystal parameters, $a = b \neq c,\ \alpha = \beta = 90{^\circ},\gamma = 120{^\circ}$ is hexagonal
Explanation
(d)
A crystal system is hexagonal if its unit cell having $a = b \neq c$ axial ratio and $\alpha = \beta = 90{^\circ}$, $\gamma = 120{^\circ},$ axial angles
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.