The present volume describes organoberyllium compounds containing at least one berylli um-carbon bond, except the beryllium carbides and cyanides. It covers the literature com pletely to the end of 1986 and includes most of the references up to mid-1987. This Gmelin volume is different from all other volumes of the series on organometallic compounds in that it is dedicated to an area of research which has virtually come to a complete standstill. Organoberyllium chemistry has never been a very popular field, and only few workers have contributed to its slow growth, as is seen by the relatively small number of publications in the field. This very modest development became stagnant in the early 1970's and was followed by a rapid decline. This exceptional fate of a branch of organometallic chemistry is only partly due to the very limited number of potential application~ of beryllium and its compounds. The compounds of this element are, in principle, at least as interesting and intriguing to scientists as those of other metals in the Periodic Table. No doubt the main reason for the apparent ban of all experimental organoberyllium chemistry is to be found in the established, and alleged, hazardous properties of beryllium compounds. Although similar hazards have been established for other organometallics where active research is still in process, e. g. , mercury and lead, these observations were absolutely lethaI for organoberyllium research.

The present volume is the fifth and for the present moment last in a series of volumes on organotitanium compounds. It covers the literature to the end of 1987. The volume continues the treatment of titanium compounds with the dinuclear and polynuclear complexes. The main part of this volume deals with the dinuclear complexes and therein (+-C5H5)2TiCl 2 is the most frequently described compound. Another key compound in this volume is the presumably oligomeric +-C5H5TiCl2 n. This volume also deals with different "titanocenes" de- scribed in the literature. There are also well-defined tri- and tetranuclear compounds, one penta- and a few hexanuclear compounds. "Black titanocene" is described together with the oligonuclear compounds. Polymers containing (+-C5H5)2TiIV units conclude this volume. As in the preceding volumes of this series, compounds of debatable existence and postulated reaction intermediates are included for completeness. A Formula Index and a Ligand Formula Index for this volume are included.