In a solid 'AB' having rock salt arrangement ( NaCl structure), 'A' atoms occupy the corners and face center of the cubic unit cell. 'B' atoms occupies all octahedral voids of the unit cell. If all the face-centered atoms along one of the axes are removed, then the resultant stochiometry of the solid is

Question

In a solid 'AB' having rock salt arrangement ( NaCl structure), 'A' atoms occupy the corners and face center of the cubic unit cell. 'B' atoms occupies all octahedral voids of the unit cell. If all the face-centered atoms along one of the axes are removed, then the resultant stochiometry of the solid is (A) AB2 (B) A2B (C) A4B3 (D) A3B4

Tardigrade Admin · Accepted Answer

There were 6 A atoms on the face-centres removing face-centred atoms along one of the axes means removal of 2 A atoms. Now, number of A atoms per unit cell <img class="img-fluid question-image" alt="Solution" src="https://cdn.tardigrade.in/q/nta/c-vdowns4umrszn97z.jpg" /> Number of B atoms per unit cell = underset( text edge centred )12 × (1/4)+ underset( textbody centred )1 = 4 Hence the resultant stoichiometry is A3B4

$A B_{2}$

$A_{2} B$

$A_{4} B_{3}$

$A_{3} B_{4}$

AB2​

A2​B

A4​B3​

A3​B4​

There were 6A atoms on the face-centres removing face-centred atoms along one of the axes means removal of 2A atoms. Now, number of A atoms per unit cell Number of B atoms per unit cell =( edge centred )12×41​​+(body centred )1=4​ Hence the resultant stoichiometry is A3​B4​

$A B_{2}$

$A_{2} B$

$A_{4} B_{3}$

$A_{3} B_{4}$