Name the crystal defect which lowers the density in an ionic crystal

Which of the following is a dichoric crystal

What is the Schotky defect? How does it affect the density of the crystal?

Which one of the following is a covalent crystal?

In a tetragonal crystal

The addition of CaCl_(2) crystal to KCl crystal a. Lowers the density of the KCl crystal b. Raises the density of the KCl crystal c. Does not affect the density of the KCl crystal d. Increases the Frenkel defects of the KCl crystal

The addition of CaCl_(2) to a KCl crystal lowers the density of the KCl crystal.

Examine the given defective crystal and {:(A^(+),B^(-),A^(+),B^(-),A^(+)),(B^(-),0,B^(-),A^(+),B^(-)),(A^(+),B^(-),A^(+),0,A^(+)),(B^(-),A^(+),B^(-),A^(+),B^(-)):} Answer the following questions : (i) What type of stoichiometirc defect is shown by the crystal ? (ii) How is the density of the crystal affected by this defect ? (iii) What type of ionic substances show such defect ?

(a) Sodium metal crystallizes in bcc structure. Its unit cell edge length is 420 pm. Calculate its density. (Atomic mass of sodium = 23 u, N_(A) = 6.022 xx 10^(23) mol^(-) ). (b) What is Frenkel defect ? How does it affect the density of a crystal ?

Which one of the following is a molecular crystal?