Crystallography - Materials science

Crystallography (from the Greek words crystallon = cold drop / frozen drop, with its meaning extending to all solids with some degree of transparency, and graphein = write) is the experimental science of determining the arrangement of atoms in solids. In older usage, it is the scientific study of crystals. Before the development of X-ray diffraction crystallography (see below), the study of crystals was based on the geometry of the crystals. This involves measuring the angles of crystal faces relative to theoretic ...

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• Crystallography - Notation
• Crystallography - Technique
• Crystallography - Materials science
• Crystallography - Biology

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Crystallography is a tool that is often employed by materials scientists. In single crystals, the effects of the crystalline arrangement of atoms is often easy to see macroscopically, because the natural shapes of crystals reflect the atomic structure. In addition, physical properties are often controlled by crystalline defects. The understanding of crystal structures is an important prerequisite for understanding crystallographic defects. A number of other physical properties are linked to crystallography. For example, the minerals i ...

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Crystallography, Crystallography - Theory, Crystallography - Notation, Crystallography - Technique, Crystallography - Materials science, Crystallography - Biology

Read more here: » Crystallography: Encyclopedia II - Crystallography - Materials science

Some materials studied using crystallography, DNA for example, do not occur naturally as crystals. Typically, such molecules are placed in solution and allowed to crystallize over days, weeks, or months through vapor diffusion. A drop of solution containing the molecule, buffer, and precipitants is sealed in a container with a reservoir containing a hygroscopic solution. Water in the drop diffuses to the reservoir, slowly increasing the concentration and allowing a crystal to form. If the concentration were to rise more quickly, the molecule would simply precipitate out of solution, resulting in disorderly granules rat ...

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Crystallography, Crystallography - Theory, Crystallography - Notation, Crystallography - Technique, Crystallography - Materials science, Crystallography - Biology

Read more here: » Crystallography: Encyclopedia II - Crystallography - Technique

X-ray crystallography is the primary method for determining the molecular conformations of biological macromolecules, particularly protein and nucleic acids such as DNA and RNA. In fact, the double-helical structure of DNA was deduced from crystallographic data. The first crystal structure of a macromolecule was solved in 1958 (Kendrew, J.C. et al. (1958) A three-dimensional model of the myoglobin molecule obtained by X-ray analysis. Nature 181, 662-666.). The Protein Data Bank (PDB) at http://www.rcsb.org is a freely accessible repository for the structures of proteins and other biological macromolecules. RasMol can be used to ...

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Crystallography, Crystallography - Theory, Crystallography - Notation, Crystallography - Technique, Crystallography - Materials science, Crystallography - Biology

Read more here: » Crystallography: Encyclopedia II - Crystallography - Biology

In many cases, an image of a microscopic object is generated by focusing the rays of the visible spectrum using a lens as in light microscopy. However, because the wavelength of visible light is long compared to atomic bond lengths and atoms themselves, it is necessary to use radiation with shorter wavelengths, such as X-rays. Employing shorter wavelengths implies abandoning microscopy and true imaging, however, because there exists no material from which a lens capable of focusing this type of radiation can be created. (That said, scientist ...

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Crystallography, Crystallography - Theory, Crystallography - Notation, Crystallography - Technique, Crystallography - Materials science, Crystallography - Biology

Read more here: » Crystallography: Encyclopedia II - Crystallography - Theory