Tables for
Volume G
Definition and exchange of crystallographic data
Edited by S. R. Hall and B. McMahon

International Tables for Crystallography (2006). Vol. G, ch. 1.1, pp. 2-3

Section 1.1.2. Past approaches to data exchange

S. R. Halla* and B. McMahonb

aSchool of Biomedical and Chemical Sciences, University of Western Australia, Crawley, Perth, WA 6009, Australia, and bInternational Union of Crystallography, 5 Abbey Square, Chester CH1 2HU, England
Correspondence e-mail:

1.1.2. Past approaches to data exchange

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The crystallographic community, along with many other scientific disciplines, has long adhered to the philosophy that experimental data and results should be routinely archived to facilitate long-term knowledge retention and access. An early approach to this, recommended by IUCr and other journals, was for authors to deposit data as hard copy (i.e. ink on paper) with the British Library Lending Division. Retaining good records is fundamental to reproducing scientific results. However, the sheer volume of diffraction data needed to repeat a crystallographic study precludes these from publication, and has led in the past to relatively ad hoc procedures for depositing supplementary data in local or centralized archives. Typically in the past, only the crystal and structure model parameters were published in the refereed paper and the underpinning diffraction information had to be archived elsewhere. Because the archived data were usually stored as paper in various unregulated formats, considerable information about the experiment and structure-refinement parameters was never retained. Moreover, the archiving of supplementary data via postal services was very slow and labour-intensive; equally, the recovery of deposited data was difficult, with information supplied as either a photocopy of the original deposition or an image taken from a microfiche.

Prior to 1970[link], when less than 9000 structures were deposited with the Cambridge Crystallographic Data Centre, data sets were still small enough to make these deposition and retrieval approaches feasible, albeit tedious. Even so, records show that very few archived data sets were ever retrieved for later use. The rationale of data storage changed radically in the 1980s. The increasing role of computers, automatic diffractometers and phase-solving direct methods in crystallographic studies led to a rapid acceleration in the number and size of structures determined and published. This was the period when fast minicomputers became affordable for laboratories, and the consequent demand for the electronic storage and exchange of information grew exponentially. Typical data-archival practices changed from using paper to magnetic tapes, as these now became the least expensive and most efficient means of storing data.


Allen, F. H. (2002). The Cambridge Structural Database: a quarter of a million crystal structures and rising. Acta Cryst. B58, 380–388.

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