The CSD–450,000 answers … but what are the questions?

Abstract

A brief survey about the development of knowledge of crystal and molecular structure based on the Cambridge Structural Database (CSD) is given. The CSD may be considered as a database of answers to the question as to which polymorph will form under given crystallization conditions. The emphasis of research over the years has moved from molecular structural geometry, to intermolecular motifs and to wider considerations of crystal packing similarity. Some experimental data items, not recorded in the CSD, place limitations on the usefulness of the CSD, in future research. Unanswered questions are discussed in the areas of crystal structure prediction, polymorphism, co-crystal and solvate formation.

Keywords:

• database
• 3D geometry
• crystal packing
• H-bonding
• crystal structure prediction

Acknowledgements

This article is based on a short talk given at the British Crystallographic Association, Spring 2007. The author gratefully acknowledges the help of colleagues over many years on the staff of CCDC, and many discussions on Crystal Structure Prediction with Professors J. Dunitz, A. Gavezzotti and W. Jones.

Subject Index

• 3DSEARCH 100

• atomic displacement parameter (ADP) 110

• Cambridge Crystallographic Data Centre (CCDC) 97, 98, 99

• Cambridge Structural Database (CSD) 97, 98, 100, 101, 102, 103, 108, 109, 110

• carbamazepine 104, 107

• co-crystals 101, 104, 110

• COMPACK 104

• coordination shells 104, 107, 111

• crystal growth 103, 111

• crystal structure prediction 97, 103, 108, 109, 112, 113

• crystallization 97, 98, 100, 102, 103, 110, 111, 112

• growth mechanisms 110

• hydrogen bond 98, 100, 109, 111

• hydrogen bond pairing 109

• lattice energy 101, 109

• melting point 101, 102, 103

• MOLPAK 108

• morphology 102, 103, 110

• ORTEP 111

• packing 97, 100, 101, 104, 105, 107, 109, 111, 112

• packing similarity 97, 104, 112

• paracetamol 110

• PLATON 111

• PLUTO 111

• polymorphism 97, 101

• polymorphs 100, 101, 103, 104, 109, 110

• PreQuest 111

• solvates 101

• terephthalic acid 107, 108

• thermal motion 101, 110, 111

• thermodynamic data 101

• three-dimensional geometry 100

• toluic acid 107, 108

• visualization 111

• Xpac 104