Powder X-ray diffraction (XRD) techniques can trace their origin to the pioneering work of Debye and Scherrer in Europe (1916) and Hull in the U.S. (1917).1 Their results dispelled the belief that grinding a single crystal to a powder would destroy crystallinity. In 1938, Hanawalt, Rinn and Frevel published over 1,000 reference XRD patterns tabulated as diffraction spacings (d-spacings) and intensities.2 More importantly, they also described a new method of materials identification that used the tabulated diffraction data and was described by the journal editor as a complete, new workable system of analysis.
Three years later, the American Society of Testing Materials (ASTM) published the first set of Hanawalt et al diffraction patterns on individual 3 x 5 in. cards, with these cards eventually referred to as Powder Diffraction File™ (PDF®) cards. In 1969, this diffraction database activity was separated from ASTM, and the new parent organization was named the Joint Committee on Powder Diffraction Standards (JCPDS). To better reflect the international scope of the organization, the name International Centre for Diffraction Data™ was added in 1978, today referred to as ICDD®.