Partial structure

Structure partielle (Fr).

The crystal structure formed by a subset of elements and their symmetry equivalents.

In describing or analyzing a crystal structure it is sometimes convenient to consider only the structure formed by the selected atoms.

Example

The structure of $BaTiO_3$ is tetragonal with a primitive unit cell and lattice constants $a$ and $c$. The partial structure of Ba has the same lattice constants whereas the partial structure of O has also a primitive cell but with the lattice constant $a_O = a/ \sqrt{2}$, $c$ being equal

See synonymous Substructure