Figure 1

Crystallographic data in CIF format. This very abbreviated example illustrate the organization of data in a CIF. “Tags” (in blue) identifying the nature of discrete data items begin with an underscore character; “data” are always ASCII character strings, but will be interpreted by computer parsers as textual or numeric – trailing integers in parentheses indicate experimental uncertainty values. White space is used as a delimiter (so text strings including white-space characters must be quoted). Keywords (in red) partition major structural components of the content; the iterated values (on a green background) are tabulated in accordance with the tags listed in the loop header. Positioning of content is not relevant – the orderly layout shown here is typical of many program outputs, but is not required.