Calcium crystallizesin `fcc` unit cell with `0.556 nm`. Calculate the density if
a. It contains `0.2%` Frenkel defects
b. It contains `0.1%` Schottky defects

Options

A. 3
B. 2
C. 1.5
D. 1

Explanation

Frenkel defects do not change the value of the theoretical density because the atom is occupying an intersitial postion instead of a lattice position.
`Z_(eff(` of Ca=4 atoms/unit cell (since it is fcc type) Since there are 0.1% Schottky defect,
So `Z_(eff)=(4-(0.1)/(100)xx4)=3.996`
`therefore rho=(Z_(eff)xxAw)/(N_(A)xxa^(3))(because 1nm=10^(-9)m=10^(-7)cm)`
`=((3.996)xx40g)/((6xx10^(23)"mol"^(-1))(0.556nmxx10^(-7)cm)^(3))=1.547g cm^(-3)`