27 Facts About X-ray crystallography


X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions.

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Since many materials can form crystals—such as salts, metals, minerals, semiconductors, as well as various inorganic, organic, and biological molecules—X-ray crystallography has been fundamental in the development of many scientific fields.

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X-ray crystallography is still the primary method for characterizing the atomic structure of new materials and in discerning materials that appear similar by other experiments.

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X-ray crystallography is related to several other methods for determining atomic structures.

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Just as an ocean wave striking a lighthouse produces secondary circular waves emanating from the lighthouse, so an X-ray crystallography striking an electron produces secondary spherical waves emanating from the electron.

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Potential of X-ray crystallography for determining the structure of molecules and minerals—then only known vaguely from chemical and hydrodynamic experiments—was realized immediately.

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X-ray crystallography has led to a better understanding of chemical bonds and non-covalent interactions.

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X-ray crystallography's conclusions were anticipated by William Henry Bragg, who published models of naphthalene and anthracene in 1921 based on other molecules, an early form of molecular replacement.

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Finally, X-ray crystallography had a pioneering role in the development of supramolecular chemistry, particularly in clarifying the structures of the crown ethers and the principles of host–guest chemistry.

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X-ray crystallography diffraction is a very powerful tool in catalyst development.

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Since the 1920s, X-ray crystallography diffraction has been the principal method for determining the arrangement of atoms in minerals and metals.

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X-ray crystallography is used routinely to determine how a pharmaceutical drug interacts with its protein target and what changes might improve it.

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X-ray crystallography is a form of elastic scattering; the outgoing X-rays have the same energy, and thus same wavelength, as the incoming X-rays, only with altered direction.

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In general, single-crystal X-ray crystallography diffraction offers more structural information than these other techniques; however, it requires a sufficiently large and regular crystal, which is not always available.

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Oldest and most precise method of X-ray crystallography is single-crystal X-ray diffraction, in which a beam of X-rays strikes a single crystal, producing scattered beams.

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Small-molecule X-ray crystallography typically involves crystals with fewer than 100 atoms in their asymmetric unit; such crystal structures are usually so well resolved that the atoms can be discerned as isolated "blobs" of electron density.

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In general, small molecules are easier to crystallize than macromolecules; however, X-ray crystallography has proven possible even for viruses and proteins with hundreds of thousands of atoms, through improved crystallographic imaging and technology.

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Small-molecule and macromolecular X-ray crystallography differ in the range of possible techniques used to produce diffraction-quality crystals.

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X-ray crystallography beams generated in large machines called synchrotrons which accelerate electrically charged particles, often electrons, to nearly the speed of light and confine them in a circular loop using magnetic fields.

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Cryo X-ray crystallography protects the sample from radiation damage, by freezing the crystal at liquid nitrogen temperatures.

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CryoX-ray crystallography methods are applied to home source rotating anode sources as well.

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Main goal of X-ray crystallography is to determine the density of electrons f throughout the crystal, where r represents the three-dimensional position vector within the crystal.

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The orientation of a particular set of sheets is identified by its three Miller indices, and let their spacing be noted by d William Lawrence Bragg proposed a model in which the incoming X-rays are scattered specularly from each plane; from that assumption, X-rays scattered from adjacent planes will combine constructively when the angle ? between the plane and the X-ray results in a path-length difference that is an integer multiple n of the X-ray wavelength ?.

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X-ray crystallography diffraction has wide and various applications in the chemical, biochemical, physical, material and mineralogical sciences.

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X-ray crystallography diffraction is analogous to a microscope with atomic-level resolution which shows the atoms and their electron distribution.

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X-ray crystallography diffraction has been used for the identification of antibiotic drugs such as: eight ß-lactam, three tetracycline and two macrolide antibiotic drugs.

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X-ray crystallography diffraction has been demonstrated as a method for investigating the complex structure of integrated circuits.

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