"Organoiron Compounds" A, Ferrocene 10 systematicalty covers the literature through the end of 1986 and includes so me references published more recently. A formula index provides ready access to the compounds covered. This volume ends the description of mononuclear unbridged disubstituted ferrocenes, 1 2 FeC HRR . The description of the unbridged disubstituted ferrocenes was initiated with lO a 1 2 "Organoiron Compounds" A, Ferrocene 7 (starting with R and R containing C and Hand 1 containing halogen at least in R\ and continuing with compounds containing 0 at least in R to form alcohols and phenols, their esters, ethers, acetals, and aldehydes), and was foltowed 1 by "Organoiron Compounds" A, Ferrocene 8 (with at least R containing 0). "Organoiron 1 Compounds" A, Ferrocene 9 treated compounds in wh ich at least R contains N, S, Se, B, or Si. This volume now comprises the rest of the disubstituted ferrocenes containing P, As, or a 1 metal at least in R . Beyond that it includes the description of alt the mononuclear unbridged trisubstituted ferrocenes, FeClOH7R1R2R3. Series A so far comprises volumes A 1 to A 10 and has been surveyed in the preface to A 7 (1980). The data in tables are given in abbreviated form without dimensions; for dimensions, explanations, and further abbreviations used, see p. X (next page). Additional remarks are given in the headings of the tables where necessary.

The present voLume is a continuation of Series 8 on the mononucLear organoiron com- pounds and describes 545 compounds. It covers the Literature compLeteLy to the end of 1983 and incLudes many references to the Literature up to mid-1984. This voLume continues the description of mononucLear organoiron derivatives by treating compounds of the type 4LFe(COh where 4L incLudes seven-, eight-, and nine-membered ring. systems. OnLy a few Larger rings of the 4LFe(COh type compounds are known, and they are aLso incLuded. In the symboL mL , n is the number of organic Ligands L in the n compound, and m is the number of Fe-C bonds formed from an L Ligand as aLready expLained in the prefaces to "KobaLt-Organische Verbindungen" 1, New SuppL. Ser., VoL. 5, 1973, and "NickeL-Organische Verbindungen" 1, New SuppL. Ser., VoL. 16, 1975. Se ries 8 so far comprises voLumes 81 to 812, and a survey of this series has been given in the preface to 87 (1981). Much of the data, particuLarLy in tabLes, is given in abbreviated form without dimensions; for expLanation see p. VIII. AdditionaL remarks, if necessary, are given in the heading of the tabLes. A formuLa index for voLumes 88, 89, and 810 wiLL be given in "Organoiron Compounds" 810.

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.