Chapter 2.5 Specification of the core CIF dictionary definition language (DDL1)

Definition and exchange of crystallographic data

First Online Edition (2006)

Part 2. Concepts and specifications

  1. S. R. Hall1,
  2. A. P. F. Cook2

Published Online: 1 JAN 2006

DOI: 10.1107/97809553602060000731

International Tables for Crystallography

International Tables for Crystallography

How to Cite

Hall, S. R. and Cook, A. P. F. 2006. Specification of the core CIF dictionary definition language (DDL1). International Tables for Crystallography. G:2:2.5:53–60.

Author Information

  1. 1

    School of Biomedical and Chemical Sciences, University of Western Australia, Crawley, Perth, WA 6009, Australia

  2. 2

    BCI Ltd, 46 Uppergate Road, Stannington, Sheffield S6 6BX, England

Publication History

  1. Published Online: 1 JAN 2006


Data dictionaries serve to identify and describe STAR File data items which are exchanged and archived. When STAR Files are written or read, dictionaries can play an important supplementary role of validating individual items and checking the overall conformance of the data structure. A STAR File dictionary contains definitions for each data item. These definitions are composed of a sequence of data attributes which, individually and collectively, specify the properties of an item. These attributes are considered to be the vocabulary of a STAR File dictionary definition language (DDL). This chapter describes the concepts and specification of the STAR File DDL dictionaries used to define the data items for core crystallographic, powder diffraction, modulated-structures and electron-density applications. For these applications, it discusses the purpose of data dictionaries, the structure of a DDL dictionary file, the function of DDL attributes and the specification of DDL attributes.


  • DDL1 specification;
  • dictionary definition language;
  • dictionaries;
  • data definitions