Section 24.3.2.1. Acquisition of information

Almost all of the information contained in the CSD has been abstracted from the published literature. Over 800 primary literature sources are cited and the earliest reference is from 1930. Much of the data has been re-keyboarded from the original literature and from hard-copy supplementary deposition documents. The CSD now acts as the official depository for some 40 major international journals. Today, an increasing proportion (around 75% in mid-2000) of the numerical information is received directly in electronic form. The switch from hard-copy input to electronic deposition has been catalysed by the development of the exchange format for crystallographic data, the crystallographic information file or CIF (Hall et al., 1991). The CIF has been adopted as the standard for the subject by the International Union of Crystallography, and is now output by nearly all of the major software packages for structure determination and refinement. Development of the CIF has also led to an increase in direct private depositions of structural data to the CSD, data that, for various reasons, are unlikely to be published through formal mechanisms.