Question
an element crystallises in fcc lattice having 400pm. calculate the maxm diameter which can be placed in a interstitial sites without disturbing the str
1) 400pm
2) 117.1 pm
3) 224.2 pm
4) 336.2 pm
Joshi sir comment
according to the given conditions
along the face of a side 4x = 400√2 or x = 100√2 here x is radius of the atom forming lattice
and along an edge 2x+2y = 400 here y is interstitial radius
so y = 200-x = 200-100√2 = 100 (2-1.414) = 100(0.586) = 58.6 pm
so diameter = 117.2