The International Centre for Diffraction Data (ICDD) maintains a database of

powder diffraction Powder diffraction is a scientific technique using X-ray, neutron, or electron diffraction on powder or microcrystalline samples for structural characterization of materials. An instrument dedicated to performing such powder measurements is call ...

patterns, the Powder Diffraction File (PDF), including the d-spacings (related to angle of diffraction) and relative intensities of observable

diffraction Diffraction is defined as the interference or bending of waves around the corners of an obstacle or through an aperture into the region of geometrical shadow of the obstacle/aperture. The diffracting object or aperture effectively becomes a s ...

peaks. Patterns may be experimentally determined, or computed based on

crystal structure In crystallography, crystal structure is a description of the ordered arrangement of atoms, ions or molecules in a crystal, crystalline material. Ordered structures occur from the intrinsic nature of the constituent particles to form symmetric pat ...

and

Bragg's law In physics and chemistry , Bragg's law, Wulff–Bragg's condition or Laue–Bragg interference, a special case of Laue diffraction, gives the angles for coherent scattering of waves from a crystal lattice. It encompasses the superposition of wave ...

. It is most often used to identify substances based on

x-ray diffraction 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 ...

data, and is designed for use with a

diffractometer A diffractometer is a measuring instrument for analyzing the structure of a material from the scattering pattern produced when a beam of radiation or particles (such as X-rays or neutrons) interacts with it. Principle Because it is relatively eas ...

. The PDF contains more than a million unique material data sets. Each data set contains diffraction, crystallographic and bibliographic data, as well as experimental, instrument and sampling conditions, and select physical properties in a common standardized format. The organization was founded in 1941 as the Joint Committee on Powder Diffraction Standards (JCPDS). In 1978, the name of the organization was changed to the current name to highlight the global commitment of this scientific endeavor. The ICDD is a nonprofit scientific organization working in the field of X-ray analysis and materials characterization. The ICDD produces

materials database A materials database is a database used to store experimental, computational, standards, or design data for materials in such a way that they can be retrieved efficiently by humans or computer programs.Powder diffraction Powder diffraction is a scientific technique using X-ray, neutron, or electron diffraction on powder or microcrystalline samples for structural characterization of materials. An instrument dedicated to performing such powder measurements is call ...

Crystallography Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids. Crystallography is a fundamental subject in the fields of materials science and solid-state physics (condensed matter physics). The wor ...

External links

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History, contents & use of the PDF

Materials Data

Advances in X-ray Analysis
��Technical articles on x-ray methods and analyses
Powder Diffraction Journal
��quarterly journal published by the JCPDS-International Centre for Diffraction Data through the Cambridge University Press
Denver X-ray Conference
��World's largest X-ray conference on the latest advancements in XRD and XRF
PPXRD-16
��Pharmaceutical Powder X-ray Diffraction Symposium Crystallography organizations Diffraction Optics institutions Organizations established in 1941 {{spectroscopy-stub