Due to $Schottky$ defect:

If a trivalent atom replaces a few silicon atoms in the three-dimensional network of silicon dioxide,what would be the type of charge on the overall structure?

Calcium crystallises in a face-centred cubic unit cell with edge length $a = 0.556 \ nm$. Calculate the density. If it contained $0.1 \%$ Frenkel defects,what is the density in $g \ cm^{-3}$?

Non-stoichiometric cuprous oxide,$Cu_{2}O$ can be prepared in the laboratory. In this oxide,the copper to oxygen ratio is slightly less than $2:1$. Can you account for the fact that this substance is a $p$-type semiconductor?

Write a short note on Frenkel defect and Schottky defect.

Which is not correct about the Schottky defects?