HCP (hexagonal close-packed)

Hexagonal close-packed (HCP) is a specific way atoms are arranged in certain metals, like titanium or cobalt, to pack them tightly together. Imagine stacking layers of spheres so that each layer fits perfectly into the gaps of the one below, creating a highly efficient, organized structure. In HCP, the layers follow a repeating pattern, resulting in a symmetrical, compact shape that minimizes space between atoms. This arrangement influences the metal’s properties, such as strength and how it responds to stress. HCP is one of the most densely packed structures, contributing to the material's durability and stability.