Romboedraalset

Romboedraalset is a term used in Dutch to refer to a set or collection of rhombohedral units, typically rhombohedra, arranged to fill space or form a lattice. In English-language contexts it may be described as a rhombohedral set or a rhombohedral tiling, depending on the emphasis on objects or on packing.

In geometry, a rhombohedron is a six-faced polyhedron whose faces are rhombi and whose opposite faces are parallel. When multiple rhombohedra are organized according to a rhombohedral lattice, the resulting arrangement can tessellate three-dimensional space or model a crystalline structure. The concept helps visualize how a primitive rhombohedral cell can generate a periodic net that describes spatial symmetry, either in a purely geometric sense or as a simplified representation of a crystal lattice.

In crystallography and materials science, the idea of a romboedraalset is related to the rhombohedral system, where lattice points are arranged with rhombus-based symmetry. Such sets can be used to illustrate stacking sequences, indexing schemes, or alternative cell representations of minerals that crystallize in rhombohedral symmetry. The term emphasizes the collective use of rhombohedral units rather than a single solid.

The term is mainly found in Dutch-language literature; in other languages it is commonly translated as rhombohedral set or rhombohedral tiling. As with similar concepts, the precise definition can vary by context, encompassing both geometric tilings and lattice descriptions of crystalline materials. See also rhombohedral lattice, rhombohedron, and rhombohedral crystal system.