Parallelohedra, old and new

Acta Crystallogr A Found Adv. 2023 May 1;79(Pt 3):273-279. doi: 10.1107/S2053273323001444. Epub 2023 Mar 31.

Abstract

It is shown that from a skewed, skeletal (edges and vertices), truncated octahedron, skewed skeletons can be derived of the other four convex parallelohedra found by Fedorov in 1885. In addition, three new nonconvex parallelohedra are produced, a counterexample to a statement by Grünbaum. This opens several new ways to view atomic positions in crystals, and new avenues in geometry.

Keywords: nonconvex parallelohedra; zonohedra.