The iOS app "Crystal Lattice" contains basic knowledge (university entrance exam level) of crystal lattices. When learning about crystal lattices, you may find it difficult to understand the 3D structure, and this app will come in handy at such times. The iOS app "Crystal Lattice" allows you to scale and rotate the 3D displayed crystal lattice. Promote 3D understanding by looking at things from various angles. For metal crystals and covalent crystals, this app explains how to calculate the coordination number, number of atoms in the lattice, atomic radius, and atomic packing factor. For ionic crystals, this app explains how to calculate the coordination number, number of ions in the lattice, ionic radius, and limiting radius ratio. Regarding metal crystals, this app explains body-centered cubic lattice, face-centered cubic lattice, and hexagonal close-packed structure. Regarding ionic crystals, this app explains NaCl type, CsCl type, ZnS (zincblende) type, and CaF2 (fluorite) type. Regarding covalent crystals, this app explains Diamond type. [details] https://app.brain-workout.org/crystallattice-e/