Appendix A: Typical Interatomic Distances in Organic Compounds and Organometallic Compounds and Coordination Complexes of the d‐ and f‐block metals

Abstract

A. 1 Introduction This Appendix presents a compilation of molecular geometry information from X-ray and neutron diffraction studies. Over the years, compilations of results from these and other techniques have appeared sporadically. The first major compilation was Chemical Society Special Publication No. 1 1 : Tables of Interatomic Distances and Configuration in Molecules and Ions [ 11. This volume summarized results obtained by diffraction and spectroscopic methods prior to 1956; a supplementary volume [2] extended this coverage to 1959. Summary tables of bond lengths between carbon and other elements were also published in Volume I11 of International Tables for X-Ray Crystallography [3]. Some years later the Cambridge Crystallographic Data Centre [4] produced an atlas-style compendium of all organic, organometallic, and metal-complex crystal structures published in the period 1960-1965 [S]. A notable compendium of structural data, without geometric information, was given in Comprehensive Organometallic Chemistry [6], covering all complexes with metal-carbon bonds. The BIDICS [7] series, which finished in 1981, provided for some years a full coverage of metal complexes, giving both bibliographic and geometric information. There have also been valuable annual summaries, without geometric information , on the structures of organometallic compounds determined by diffrac-tion methods [8]. The production of further comprehensive compendia of X-ray and neutron dif-fraction results has been precluded by the steep rise in the number of published crystal structures, as illustrated by Figure A.l. Printed compilations have been effectively superseded by computerized databases. In particular, the Cambridge Structural Database (CSD) now (October 1992) contains bibliographic, chemical, and numerical results for over 100,000 organo-carbon crystal structures. This machine-readable file fulfils the function of a comprehensive structure-by-structure compendium of molecular geometries. However, the amount of data now held in CSD is so large that there is also a need for concise, printed tabulations of average molecular dimensions.