Question

Answer the following for a face centered unit cell. answers should be numerical. r=6.00

edge in terms of r, the lattice pt radius

i know that for a primitive cubic unit cell, you would muliply 2 by 6 = 12. but what formula would u use for a FCC???

Please help. thanks

Answer 1

(12^2) +(12^2) = x
sqrt(x)=ans

Answer 2

^wrong

Answer 3

I don' understand the first two sentences (actually only parts of sentences) but the radius and edge length of the unit cell for the fcc is
4r=a*2^1/2
There are 4 atoms/unit cell for a fcc.