Which of the following best defines interstitial voids in solids?
Spaces left between atoms or ions due to packing arrangements
Spaces left between grains in a crystalline lattice
Spaces occupied by foreign atoms or ions in the crystal structure
Spaces between different layers of a crystal lattice
Interstitial voids are the spaces left between atoms or ions in a solid due to their packing arrangements. These voids are formed when atoms or ions are closely packed in a crystalline lattice, and some spaces are left vacant between them. These voids can be occupied by foreign atoms or ions, leading to the formation of solid solutions.