Extensions to the STAR File syntax.

The STAR File [Hall J. Chem. Inf. Comput. Sci. 1991, 31, 326-333; Hall and Spadaccini J. Chem. Inf. Comput. Sci. 1994, 34, 505-508] format represents a universal language adopted for electronic data and metadata exchange in the molecular-structure sciences [Hall et al. Acta Crystallogr. Sect. A 1991, 47, 655-685; International Tables for International Tables for Crystallography. Vol. G: Definition and exchange of crystallographic data; Springer: Dordrecht, The Netherlands, 2005; Allen et al. J. Chem. Inf. Comput. Sci. 1995, 35, 412-427] and used by the International Union for Crystallography for publication submissions and database depositions. This paper describes an extended STAR syntax that facilitates richer and more specific data definition and typing and a commensurate improvement in precise data description.