Question

what is scc, bcc, fcc

Answer 1

#SCC - simple cubic centre means just 8 atoms at the 8 vertices;
hence per unit cell no of atom is -(8×1/8)=1 [here the contribution of each corner is 1/8]

#BCC-body centred cubic in which 8 atoms at 8 corner nd an atom at the body centre;
hence per unit cell no of atom-(1×1/8)+1=2
[contribution of body centre-1]

#FCC-face centred cubic - 8 atoms at 8 corners+ 6 atoms at each face(no of faces in a cubic system:6) centre;
hence no of atoms per unit cell:(1×1/8)+(6×1/2)=4
[contribution of each face centre is 1/2]