Explanation:
Formation of crystals starts with formation of ions. After the formation of ions the bond formation takes place between the ions.
Bond making between the ions give rise to formation of cubic unit cell by placing them in such a fashion that it forms a shape of a cube.
These cube are then arranged in a repeated pattern which ultimately leads to the formation of crystals.
Hence, the order of steps:
Step 1 : Formation of ions
Step 2: Formation of ionic bonds
Step 3: Formation of cubes
Step 4: Formation of crystals