GENERAL GEOLOGY

Detailed explanation-1: -In a unit cell, the number of coordinates of an atom is the number of atoms that it touches. The closest hexagonal packed (hcp) has a coordinating number of 12 and contains six atoms per unit cell. The face-centered cubic (fcc) has a total of 12 coordinates and contains 4 atoms per unit cell.

Detailed explanation-2: -The unit cell consists of lattice points that represent the locations of atoms or ions. The entire structure then consists of this unit cell repeating in three dimensions, as illustrated in Figure 4.1. 1.

Detailed explanation-3: -The smallest repeating unit of a crystal lattice is the unit cell. The simple cubic unit cell contains only eight atoms, molecules, or ions at the corners of a cube.

Detailed explanation-4: -The characteristics of a unit cell are: (i) The dimensions are measured along the three edges, a, b and c. These edges can form different angles, they may be mutually perpendicular or may not. (ii) The angles held by the edges are (between b and c) (between a and c) and (between a and b).