Hexagonal systems. a chemistry-motivated excursion to combinatorial geometry

Ivan Gutman

Hexagonal systems are geometric objects obtained by arranging mutually congruent regular hexagons in the plane. Such geometric features are usually not considered in secondary-school courses of mathematics, although these are easy-to-grasp and probably interesting to students. In this paper the elements of the theory of hexagonal systems are outlined. We indicate some properties of hexagonal systems that secondary-school students could prove themselves, as well as a few less easy results and open problems.