Crystals are defined as a 3D periodic arrangement of atoms in space, known as a lattice, with a motif or basis of atoms associated with each lattice point. A lattice is a 3D periodic arrangement of points without the atoms. Together, the lattice and motif define the crystal structure. There are 14 possible lattice arrangements, known as Bravais lattices, which are categorized into 7 crystal systems based on their symmetry properties. The lattice and basis completely specify the crystal structure.

3. Matter Crystalline Amorphous Solid Liquid Gas

4. Crystal?

5. A 3D translationally periodic arrangement of atoms in space is called a crystal.

6. Air, Water and Earth A two-dimensional periodic pattern by a Dutch artist M.C. Escher

7. Lattice?

8. A 3D translationally periodic arrangement of points in space is called a lattice.

9. A 3D translationally periodic arrangement of atoms Crystal A 3D translationally periodic arrangement of points Lattice

10. What is the relation between the two? Crystal = Lattice + Motif Motif or basis: an atom or a group of atoms associated with each lattice point

11. Crystal=lattice+basis Lattice: the underlying periodicity of the crystal, Basis: atom or group of atoms associated with each lattice points Lattice: how to repeat Motif: what to repeat

12. + Love Pattern Love Lattice + Heart =

13. Formula for Love Potion? Mix one molecule of potassium iodide with two molecules of sulfur KI + 2S = KISS

15. Lattice Finite or infinite?

16. Primitive cell Primitive cell Nonprimitive cell

18. Lattice Parameters Lengths of the three sides of the parallelopiped : a, b and c. The three angles between the sides:  ,  , 

20. The six lattice parameters a , b , c ,  ,  ,  The cell of the lattice lattice crystal + Motif