Woodcock, " Entropy difference between the face-centred cubic and hexagonal close-packed crystal structures, " Nature, 385(6612):141-143 (1997).L. V. Woodcock. Entropy difference between the face-centred cubic
Although most colloidal crystals prepared by self-assembly are entropy favorable face-centered cubic (fcc) and hexagonal close packing (hcp) stacking, it has been shown that many other complex crystal structures could be fabricated by controlled or template-directed self-assembly, which may possess ...
different crystal structures of the same compound (ca. 1% of compounds present in CSD have been studied in more than one polymorphic form), gives similar conclusions. Such differences as do occur, are usually confined to torsion angles, discrepancies in bond distances and angles falling within ...
directional. This means that each atom tends to surround itself by as many others as possible. This results in a close packing, similar to that of spheres of equal radius, and yields three distinct systems: close-packed (face-centered) cubic, hexagonal close-packed, and body-centered cubic....
that link the two structures. This process, while computationally challenging, will provide an exhaustive list of deformations connecting the two periodic unit cells. However, as detailed in the next section, the symmetry of the underlying structures can be exploited to greatly simplify this process....
The tetragonal crystal system has similar unit cells to the cubic, but the sizes are not equal. As an example, the body-centered tetragonal (BCT) crystal lattice unit cell is shown in Figure 2.13. Tin forms a tetragonal unit cell. The tetragonal is similar because the axes are all normal...
The crystalline forms of silicon carbide that most interest technological applications arealpha(α-SiC) andbeta(β-SiC). Alpha has a hexagonal structure, while beta has a face-centered cubic structure. In literature, the symbols H-SiC and C-SiC are often used to distinguish the alpha and beta...
A2-related crystal structures considered for the β/γ-Cu–Sn high-temperature phases: Cubic unit cells in clinographic view for the (a) A2 structure (β phase,\(Im\overline{3}m\)), (b) possibly existing B2 superstructure reported as separate phase in Ref.13(\(Pm\overline{3}m\)), ...
Also, the observed FT-PAMAM crystals showed a dendrimer generation dependency on the crystal structure and lattice constant. The producing crystals show quite different symmetries if the size ratios of building blocks is varied. Importantly, two different crystallographic symmetries (cubic and hexagonal)...
Consequently, the more carbon atoms in martensite, the greater is the displacement of iron atoms, producing tetragonal unit cells, with one axis greater than the other two, instead of the cubic unit-cell structure of body-centered cubic ferrite without carbon. Increasing carbon content significantly...