If the atoms of an element have the radius r,then in a primitive cubic unit cell,calculate
(A) the length of the face diagonal
(B) the length of the body diagonal

2

(a)

Out of NaCl and CsCl,which is more stable and why?

2

(a)

In a crystal,Frenkel defect is not shown by alkali metal halides but silver halides show.Why?

2

(a)

What is the arrangement of atoms in the lattice structure of diamond and give contribution of each C atom?

2

(a)

Lithium borohydride,LiBH₄,crystallize in an orthorhombic system with 4 molecules per unit cell.The unit cell dimensions are: a=6.81\(\overset { 0 }{ A } \) ,b=4.43\(\overset{0}{A}\) and c=7.17\(​​\overset{0}{A}\).Calculate the density of the crystal.Take atomic mass of Li=7,B=11 and H=1 a.m.u.

2

(a)