Iron changes its crystal structure from body-centred to cubic close-packed structure when heated to 916⁰C.Calculate the ratio of the bcc crystal to that of ccp crystal,assuming that the metallic radius of the atom does not change.

Lithium iodide crystal has a face-centred cubic unit cell.If the edge length of the unit cell is 620pm,determine the ionic radius of I^-ion.

You are given marbles of diameter 10mm.They are to be placed such that their centres are lying in a square bound by four lines each of length 40mm.What will be the arrangement of marbles in a plane so that maximum number of marbles can be placed inside the area?Sketch the diagram and derive an expression for the number of marbles per unit area.

Calcium metal crystallize in a face-centred cubic lattice with edge length of 0.556nm.Calculate the density of the metal if contains (i)0.5% Frenkel defects(ii)0.2% Schottky defects.

A compound consisting of the monovalent ions A⁺,B^- crystallizes in the body-centred cubic lattice.(i)What is the of the compound? (ii)If one one of A⁺ions  from the corner is replaced by a monovalent ion C⁺,what would be the simplest formula of the resulting compound?

If silver iodide crystallizes in a zinc blende structure with I^-ions forming the lattice,then calculate fraction of the tetrahedral voids occupied by Ag⁺ ions

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.

Show that in cubic packed structure, eight tatrahedral voids are persent per unit cell.

With the help of a labelled diagram show that there are four octahedral voids per unit cell in cubic close packed structure.