GEOLOGY

Detailed explanation-1: -Contribution of corner particles: A particle at the corner of a unit cell is shared by eight-unit cells.

Detailed explanation-2: -An atom on an edge is shared by four unit cells, and an atom on a corner is shared by eight unit cells.

Detailed explanation-3: -The simple cubic unit cell is delineated by eight atoms, which mark the actual cube. These are corner atoms, so each one only contributes one eighth of an atom to the unit cell, thus giving us only one net atom.

Detailed explanation-4: -A FCC unit cell contains four atoms: one-eighth of an atom at each of the eight corners (8×18=1 atom from the corners) and one-half of an atom on each of the six faces (6×12=3 atoms from the faces).

Detailed explanation-5: -You will notice that the atoms or ions at the edges of each face, or at the corners, are not complete spheres. In the simple cubic cell, each corner atom is shared by 8 different unit cells.