International Centre for Diffraction Data

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 ICDD is a nonprofit scientific organization working in the field of X-ray analysis and materials characterization.

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 also publishes the journals Advances in X-ray Analysis and Powder Diffraction.