Question

In a CCP structure of compound AB, A atoms are present at octahedral voids. What is the ratio of 2nd C.No to 1st C
for an atom B located at corner?
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Answer 1

Given :

• CCP structure ( cubic closed packing ) is given.

• A atoms are present at octahedral void.

Find :

• The ratio of 2nd C.No to 1st C.N for an atom B located at corner.

Solution :

• In this as CCP structure is given and A atoms are present at octahedral void . Octahedral voids are surrounded by six atoms which is sitting at the corners of a regular octahedron is called an octahedral void.

• In CCP the atoms are present at the corners and at the face centers of the cube.

• So, for the 1st C.N , B atoms are surrounded by the six face centers . So, it's C.N 1 = 6 , as 6 faces are present in the cube.

• For the 2nd C.N. , B atoms are surrounded by the edge centre present in the cube and there are 12 edges are present so the edge centres. So, C.N 2 = 12 .

• So , the ratio of C.N 2 / C.N1 = 12/6 = 2.

• The ratio of 2nd C.No to 1st C.N for an atom B located at corner is 2.

• The ratio of 2nd C.No to 1st C.N for an atom B located at corner is 2.