What are coordination number (nearest neighbour) in a BCC at distance of (a√3/2) and next nearest neighbour at distance (a) and next to next nearest neighbour at distance (a√2) ?.

Coordination Numbers:

(1) The nearest neighbour distance is half of body diagonal (a) root 3/2 (along body diagonal) thereforecoordination number for a given atom in BCC unit cell is 8.

(2) The next nearest neighbour are 6 at distance (a)Lattice parameter.

(3) 3^rd neighbour (Next to Next nearest neighbour) are(12) at distance (a root 2) ( All corner along face diagonal in x,y and Z plane).