hexagonal

Hexagonal is a term used to describe anything relating to the number six or to a six-sided polygon. In geometry, a hexagon is a polygon with six sides and six interior angles; the regular hexagon has all sides and angles equal and tessellates the plane, enabling efficient tiling without gaps. This property appears in natural patterns such as honeycombs and in certain engineered layouts and grid systems.

In crystallography and materials science, hexagonal refers to the hexagonal crystal system, whose unit cell is a hexagonal prism. A common packing arrangement is hexagonal close packing (hcp), seen in metals like magnesium and titanium. Graphite is a notable hexagonal structure, consisting of layers of carbon atoms arranged in hexagonal rings.

In chemistry, hexagonal geometry often appears in ring compounds. The benzene ring is a classic example: six carbon atoms arranged in a hexagonal ring with alternating bonds. Many other aromatic and heterocyclic compounds feature hexagonal planning as part of their core structure.

In mathematics, hexagonal numbers form a sequence of figurate numbers given by n(2n−1), with initial terms 1, 6, 15, 28, and so on. These numbers count dots arranged in a hexagonal lattice.

Across fields, the term hexagonal connotes symmetry and tiling efficiency, from molecular structures to architectural patterns. It is used in nomenclature for specific coordination geometries, crystalline systems, and abstract number sequences.