X-ray diffraction

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The study of the arrangement of atoms in a crystal, by interpreting the diffraction patterns of X-rays as they interact with the crystal lattice.

Crystallography: The study of the geometric properties of crystals, including crystal structures, crystal symmetry, and the relationship between atomic arrangement and crystal form.
X-ray sources and detection: The components and principles of an X-ray diffraction setup, including X-ray sources and detectors, focusing and monochromation of X-rays for optimal signal-to-noise ratio, and temperature control.
X-ray diffraction theory: The fundamental principles of X-ray diffraction, including Bragg's Law, the reciprocal lattice, and the diffraction of X-rays by crystals.
Sample preparation: The process of selecting, preparing, and handling mineral samples for X-ray diffraction analysis, including cleaning, crushing, grinding, and mounting.
Data collection: The techniques used to obtain X-ray diffraction data, including single-crystal, powder, and grazing-incidence diffraction.
Data analysis: The methods used to interpret X-ray diffraction data, including the identification and refinement of crystal structures, and the determination of crystal symmetry and lattice parameters.
Applications: The many applications of X-ray diffraction to mineralogical problems, including phase identification, quantification, and characterization, as well as structural and thermodynamic studies.
Single crystal X-ray diffraction: This method involves analyzing a single crystal of a mineral under X-ray radiation to determine its internal crystal structure.
Powder X-ray diffraction: This method involves analyzing a powder of a mineral under X-ray radiation to determine its crystal structure.
Thin film X-ray diffraction: This method involves analyzing a thin film of a mineral on a substrate under X-ray radiation to determine its crystal structure.
Small angle X-ray scattering: This method involves analyzing the scattering of X-rays at small angles from a mineral to determine its particle size and distribution.
High-resolution X-ray diffraction: This method involves analyzing the diffraction patterns of a mineral at high resolution to determine its crystal structure and strain.
Time-resolved X-ray diffraction: This method involves analyzing the diffraction patterns of a mineral over time to determine its real-time structural changes.
Resonant X-ray diffraction: This method involves analyzing the diffraction patterns of a mineral at X-ray wavelengths that coincide with specific electronic transitions to determine its electronic and magnetic properties.
Anomalous X-ray diffraction: This method involves analyzing the diffraction patterns of a mineral at X-ray wavelengths that lie outside the normal range to determine the positions of specific elements within the crystal.
Grazing incidence X-ray diffraction: This method involves analyzing the diffraction patterns of a mineral at low angles of incidence under X-ray radiation to determine its surface structure and orientation.
Energy-dispersive X-ray diffraction: This method involves analyzing the diffraction patterns of a mineral using an energy-dispersive X-ray detector to determine its crystal structure and chemical composition.
- "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."
- "By measuring the angles and intensities of these diffracted beams, a crystallographer can produce a three-dimensional picture of the density of electrons within the crystal."
- "From this electron density, the mean positions of the atoms in the crystal can be determined, as well as their chemical bonds, their crystallographic disorder, and various other information."
- "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."
- "In its first decades of use, this method determined the size of atoms, the lengths and types of chemical bonds, and the atomic-scale differences among various materials, especially minerals and alloys."
- "The method also revealed the structure and function of many biological molecules, including vitamins, drugs, proteins, and nucleic acids such as DNA."
- "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."
- "X-ray crystal structures can also account for unusual electronic or elastic properties of a material, shed light on chemical interactions and processes, or serve as the basis for designing pharmaceuticals against diseases."
- "X-ray crystallography is related to several other methods for determining atomic structures. Similar diffraction patterns can be produced by scattering electrons or neutrons, and neutron scattering can be similarly interpreted by Fourier transformation."
- "If single crystals of sufficient size cannot be obtained, various other X-ray methods can be applied to obtain less detailed information; such methods include fiber diffraction, powder diffraction, and (if the sample is not crystallized) small-angle X-ray scattering (SAXS)."
- "If the material under investigation is only available in the form of nanocrystalline powders or suffers from poor crystallinity, the methods of electron diffraction, transmission electron microscopy, and electron crystallography can be applied for determining the atomic structure."