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.