The structure of MgO is similar to NaCl the number of next nearest neighbour of Mg is –a) 4b) 6c) 12d) 8Please answer with details and what does it mean by “next nearest neighbour’’?

Hello Student,

Nearest neighbours to a FCC latice would be 12 w.r.t a face centre or corner at a distance of a/√2.

For Next nearest neighbours, count the Nearest neighbours with respect to corner atom as you would do in simple cubic which would come out to be 6 at a distance of a.

Please look at the image carefully, it will make your concept clear.

Approved