Question

in a unit cell A,B,C and D are present at corners, face centre, body centre and edges centre respectively. If atoms touching one of the plane passing through 2 diagonals opposite edges are removed. Then the formula off compound is.

Answer 1

Hello mate!!!


In a unit cell , A atoms present at corners
B atoms present at face centres
C atoms present at body centres
D atoms present at edge centres

Now, after removing atoms lying on the plane passing through two diagonally opposite edge . Hence, there are 4 corner atoms , two face centre atoms , one body centre atom and two edge center atoms are removed .
So, now, atoms left at corner = 8 - 4⇒eff number of atoms = 4 × 1/8 = 1/2
atoms left at face centre = 6 - 2 = 4⇒eff number of atom = 4 × 1/2 = 2
atoms left at body centre = 1 - 1 = 0⇒eff number of atom = 0/1 = 0
atoms left at edge centre = 12 - 2 = 10⇒eff number of atom = 10 × 1/4 = 2.5
Hence, ratio of A : B : C : D = 0.5 : 2 : 0 :2.5 = 1 : 4 : 0 : 5
Hence, compound formula = AB₄C₀D₅



Hope it helps you!!