X-ray crystallography

X-ray crystallography,

the study of crystal structures through X-ray diffraction techniques. When an X-ray beam bombards a crystalline lattice in a given orientation, the beam is scattered in a definite manner characterized by the atomic structure of the lattice. This phenomenon, known as X-ray diffraction, occurs when the wavelength of X-rays and the interatomic distances in the lattice have the same order of magnitude. In 1912, the German scientist Max von Laue predicted that crystals exhibit diffraction qualities. Concurrently, W. Friedrich and P. Knipping created the first photographic diffraction patterns. A year later Lawrence Bragg successfully analyzed the crystalline structures of potassium chloride and sodium chloride using X-ray crystallography, and developed a rudimentary treatment for X-ray/crystal interaction (Bragg's Law). Bragg's research provided a method to determine a number of simple crystal structures for the next 50 years. In the 1960s, the capabilities of X-ray crystallography were greatly improved by the incorporation of computer technology. Modern X-ray crystallography provides the most powerful and accurate method for determining single-crystal structures. Structures containing 100–200 atoms now can be analyzed on the order of 1–2 days, whereas before the 1960s a 20-atom structure required 1–2 years for analysis. Through X-ray crystallography the chemical structure of thousands of organic, inorganic, organometallic, and biological compounds are determined every year.

Bibliography

See M. Buerger, X-Ray Crystallography (1980).

X-ray crystallography

The study of crystal structure by x-ray diffraction techniques. For the experimental aspects of x-ray diffraction See X-ray diffraction

Structurally, a crystal is a three-dimensional periodic arrangement in space of atoms, groups of atoms, or molecules. If the periodicity of this pattern extends throughout a given piece of material, one speaks of a single crystal. The exact structure of any given crystal is determined if the locations of all atoms making up the three-dimensional periodic pattern called the unit cell are known. The very close and periodic arrangement of the atoms in a crystal permits it to act as a diffraction grating for x-rays. See Crystallography

x-ray crystallography

[′eks ‚rā ‚krist·əl′äg·rə·fē] (crystallography) The study of crystal structure by x-ray diffraction techniques. Also known as roentgen diffractometry.

X-ray crystallography

crystallography

[kris″tah-log´rah-fe] the science dealing with the study of crystals.x-ray crystallography the determination of the three-dimensional structure of molecules by means of diffraction patterns produced by x-rays of crystals of the molecules.

X-ray crystallography

a powerful technique for determining the structure of crystalline substances by measuring the diffraction patterns produced when a beam of X-rays is passed through the crystal. X-ray crystallography has provided information on the 3-D structure of PROTEINS, NUCLEIC ACIDS, DRUGS, HORMONES, VITAMINS and so on, from which atomic models can be built. Knowledge of the structure of such molecules has provided insight into how they function, and is useful in PROTEIN ENGINEERING.

单词	x-ray crystallography
释义	x-ray crystallography x-ray crystallography n. The study of crystal structure by means of x-ray diffraction. X-ray crystallography n (General Physics) the study and practice of determining the structure of a crystal by passing a beam of X-rays through it and observing and analysing the diffraction pattern produced X-ray crystallography X-ray crystallography, the study of crystal structures through X-ray diffraction techniques. When an X-ray beam bombards a crystalline lattice in a given orientation, the beam is scattered in a definite manner characterized by the atomic structure of the lattice. This phenomenon, known as X-ray diffraction, occurs when the wavelength of X-rays and the interatomic distances in the lattice have the same order of magnitude. In 1912, the German scientist Max von Laue predicted that crystals exhibit diffraction qualities. Concurrently, W. Friedrich and P. Knipping created the first photographic diffraction patterns. A year later Lawrence Bragg successfully analyzed the crystalline structures of potassium chloride and sodium chloride using X-ray crystallography, and developed a rudimentary treatment for X-ray/crystal interaction (Bragg's Law). Bragg's research provided a method to determine a number of simple crystal structures for the next 50 years. In the 1960s, the capabilities of X-ray crystallography were greatly improved by the incorporation of computer technology. Modern X-ray crystallography provides the most powerful and accurate method for determining single-crystal structures. Structures containing 100–200 atoms now can be analyzed on the order of 1–2 days, whereas before the 1960s a 20-atom structure required 1–2 years for analysis. Through X-ray crystallography the chemical structure of thousands of organic, inorganic, organometallic, and biological compounds are determined every year. Bibliography See M. Buerger, X-Ray Crystallography (1980). X-ray crystallography The study of crystal structure by x-ray diffraction techniques. For the experimental aspects of x-ray diffraction See X-ray diffraction Structurally, a crystal is a three-dimensional periodic arrangement in space of atoms, groups of atoms, or molecules. If the periodicity of this pattern extends throughout a given piece of material, one speaks of a single crystal. The exact structure of any given crystal is determined if the locations of all atoms making up the three-dimensional periodic pattern called the unit cell are known. The very close and periodic arrangement of the atoms in a crystal permits it to act as a diffraction grating for x-rays. See Crystallography x-ray crystallography [′eks ‚rā ‚krist·əl′äg·rə·fē] (crystallography) The study of crystal structure by x-ray diffraction techniques. Also known as roentgen diffractometry. X-ray crystallography crystallography [kris″tah-log´rah-fe] the science dealing with the study of crystals.x-ray crystallography the determination of the three-dimensional structure of molecules by means of diffraction patterns produced by x-rays of crystals of the molecules. X-ray crystallography a powerful technique for determining the structure of crystalline substances by measuring the diffraction patterns produced when a beam of X-rays is passed through the crystal. X-ray crystallography has provided information on the 3-D structure of PROTEINS, NUCLEIC ACIDS, DRUGS, HORMONES, VITAMINS and so on, from which atomic models can be built. Knowledge of the structure of such molecules has provided insight into how they function, and is useful in PROTEIN ENGINEERING. See XRC See XRCThesaurusSeecrystallography
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