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The early crystal structures included chymotrypsin (PDB file 2CHA), [17] chymotrypsinogen (PDB file 1CHG), [18] trypsin (PDB file 1PTN), [19] and elastase (PDB file 1EST). [20] They also were the first protein structures that showed two near-identical domains, presumably related by gene duplication. One reason for their wide use as textbook and ...
In crystallography, crystal structure is a description of ordered arrangement of atoms, ions, or molecules in a crystalline material. [1] Ordered structures occur from intrinsic nature of constituent particles to form symmetric patterns that repeat along the principal directions of three-dimensional space in matter.
The fcc structure is a close-packed structure unlike the bcc structure; thus the volume of the iron decreases when this transformation occurs. Crystallography is useful in phase identification. When manufacturing or using a material, it is generally desirable to know what compounds and what phases are present in the material, as their ...
Similar to the ideal hcp structure, the perfect dhcp structure should have a lattice parameter ratio of = In the real dhcp structures of 5 lanthanides (including β-Ce) / variates between 1.596 (Pm) and 1.6128 (Nd). For the four known actinides dhcp lattices the corresponding number vary between 1.620 (Bk) and 1.625 (Cf).
It is found as a crystal structure in chemistry where it is usually known as a "type I clathrate structure". Gas hydrates formed by methane, propane, and carbon dioxide at low temperatures have a structure in which water molecules lie at the nodes of the Weaire–Phelan structure and are hydrogen bonded together, and the larger gas molecules ...
Apart from that, several crystal structure databases are freely available for primarily educational purposes, in particular mineralogical databases and educational offshoots of the COD. Crystallographic databases can specialize in crystal structures, crystal phase identification, crystallization, [12] crystal morphology, or various physical ...
Fundamentals of crystallography: crystal systems, Miller Indices, symmetry elements, bond lengths and radii, theoretical density; Crystal and glass structure prediction: Pauling's and Zachariasen’s rules; Phase diagrams and crystal chemistry (including solid solutions) Imperfections (including defect chemistry and line defects) Phase transitions
The staff at the CCDC curate the database of small-molecule organic and metal-organic crystal structures and make these available for download by the public. They also create and maintain a suite of cheminformatics software that may be used to apply the data to applications in the life sciences, including crystal engineering and materials science.