e cubic unit cell is the smallest repeating unit when all angles are 90o and all lengths are equal (figure 12.1.b) with each axis being defined by a Cartesian coordinate (x,y,z). Each cubic cell has 8 atoms in each corner of the cube, and that atom is shared with 8 neighboring cells. In the Body Centered Cubic Cell (BCC) there is an additional atom in the center of the cube, and in the face centered cubic cell, an atom is shared between two unit cells along the face. Please watch the YouTube video as this can help a lot.
explains the structure of cubic unit cells in crystallography. It describes the three types: simple cubic (atoms at each corner), body-centered cubic (BCC, with an extra atom in the center), and face-centered cubic (FCC, with atoms on each face). Each corner atom is shared among eight adjacent cells, and the structure helps define how atoms are arranged in a solid. @belfrob99