The International Centre for Diffraction Data (ICDD) maintains a database of powder diffraction patterns, the Powder Diffraction File (PDF), including the d-spacings (related to angle of diffraction) and relative intensities of observable diffraction peaks. Patterns may be experimentally determined, or computed based on crystal structure and Bragg's law. It is most often used to identify substances based on x-ray diffraction data, and is designed for use with a diffractometer. The database is exhaustive, over 500,000 entries as of 2006; computer algorithms allow rapid peak matching. 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, founded by, and dedicated to scientists working in the field of X-ray analysis and materials characterization. The ICDD produces materials databases, characterization tools, and educational materials, as well as organizing and supporting global workshops, clinics and conferences. It provides the scientific community with the tools required for X-ray analysis while continuing to educate and inform current and future scientists in the field.
The Vision - The International Centre for Diffraction Data will continue to develop tools and support the education required for materials analyses of tomorrow.
The Mission - The International Centre for Diffraction Data will continue to be the world center for quality diffraction and related data to meet the needs of the technical community. ICDD promotes the application of materials characterization methods in science and technology by providing forums for the exchange of ideas and information.
Products and services of the ICDD include the Powder Diffraction File databases, educational workshops, clinics and symposia as well as sponsorship of the Denver X-ray Conference. The ICDD also publishes the journals Advances in X-ray Analysis and Powder Diffraction.
As mentioned above, the Powder Diffraction File contains powder diffraction data and is designed to work with a diffractometer to identify unknown materials. With every entry, the database also contains bibliographic references, chemistry descriptions, structural classifications, crystallographic and physical properties.