Flat Framework 2D Hexagonal and Square Packing

The video tutorial explains two types of close packing in two dimensions: square close packing and hexagonal close packing. In square close packing, spheres are arranged in rows where each sphere is in contact with four neighbors, forming a square pattern. This arrangement is referred to as a a a A type, with a coordination number of 4. In hexagonal close packing, spheres are arranged in an ABAB pattern, where each sphere is in contact with six neighbors, forming a hexagonal pattern. The coordination number for this arrangement is 6. The video highlights the differences between these packing types and their respective coordination numbers.

What shapes are formed when joining the centers of neighboring spheres in square close packing?

Explain the difference between the coordination numbers in square close packing and hexagonal close packing.