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 ca ...

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

diffraction Diffraction is the deviation of waves from straight-line propagation without any change in their energy due to an obstacle or through an aperture. The diffracting object or aperture effectively becomes a secondary source of the Wave propagation ...

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

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

and

Bragg's law In many areas of science, Bragg's law — also known as Wulff–Bragg's condition or Laue–Bragg interference — is a special case of Laue diffraction that gives the angles for coherent scattering of waves from a large crystal lattice. It descr ...

. It is most often used to identify substances based on

x-ray diffraction X-ray diffraction is a generic term for phenomena associated with changes in the direction of X-ray beams due to interactions with the electrons around atoms. It occurs due to elastic scattering, when there is no change in the energy of the waves. ...

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 A typical diffractometer c ...

. 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. In 1978, the current name was adopted 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. It produces materials databases, characterization tools, and educational materials, as well as organizing and supporting global workshops, clinics and conferences. Products and services of the ICDD include the paid subscription based Powder Diffraction File databases (PDF-2, PDF-4+, PDF-4+/Web , PDF-4/Minerals, PDF-4/Organics, PDF-4/Axiom, and ICDD Server Edition), educational workshops, clinics, and symposia. It is a sponsor of the Denver X-ray Conference and the Pharmaceutical Powder X-ray Diffraction Symposium. It also publishes the journals ''Advances in X-ray Analysis'' and ''Powder Diffraction''. In 2019, Materials Data, also known as MDI, merged with ICDD. Materials Data creates JADE software used to collect, analyze, and simulate XRD data and solve issues in an array of materials science projects. In 2020, the ICDD and the Cambridge Crystallographic Data Centre, which curates and maintains the Cambridge Structural Database, announced a data partnership.

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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

See also

References

External links