body centered cubic unit cell
the coordination number of each sphere in this structure is 8 (each sphere is in contact with with four spheres in the layer above and four spheres in the layer below). Contains the equivalent of two spheres/atoms per unit cell. Alkali metals all BCC, Cr, Mn, Fe are all BCC.
a= 4r/ square root of 3
this relationship can be used to determine the atomic radius r and the edge length a of a body centered cubic cell