Q6

(a) Briefly (in less than 40 words) explain why? (3)

(i) Effective number of atoms in diamond cubic is more but packing efficiency is less.

(ii) For X-rays diffraction K(alfa) radiation is used instead of K(beta).

(iii) In list of Bravais lattices, FCC is present but not FCT.

(b) Find the local packing arrangement in the ionic crystal CaO and calculate the density of the crystal. Given the ionic radii Ca^2+ and 0^2- are 0.94 and 1.32 Angstrom respectively. Atomic masses of Ca and 0 are ~40 and 16 amu, respectively.

(c) List and explain the factors responsible for the formation of non-crystalline solids. (please answer step wise and in an easy way for every part, thank you)