Spiral Substructures of Nanowires Determined by the Universal Building Unit (Tetrablock)

On the example of linear substructures of Mn modifications, we show two types of spirals formed by tetrablocks assembled along their sides, namely, seven-vertex unions of four tetrahedra. Experimental data that confirm the existence of spiral packings of this kind in the structures of metallic nanowires are discussed. The noncrystallographic symmetry of the spiral packing of tetrablocks enables us to adequately describe the crystalline and noncrystalline tetrahedral structures that are also present in densely packed metals.