E.O. Fischer received the Nobel prize in 1973 for the investigations of complexes with a formal metal atom-carbon double bond. Among these, the Iron-Carbene species is readily available and has proved to be a versatile reagent in organic syntheses. It is rather simple to tune the electronicproperties of this Fischer Carbene and to control reactivity and stereospecificity of the reagent in, e.g., cyclopropanation reactions. This first volume of the "Scripts in Inorganic and Organome- tallic Chemistry" addresses graduate students in the fields ofcoordination compounds and organic synthesis. It covers the chemistry and structural aspects of iron-carbon com- pounds with a iron-carbon double bond. The first part deals with the carbene moiety, the second with vinylidene ligands.

The GmeLin series "Organometallic Compounds" comprises compounds containing at least one carbon-to-metal bond (except cyano compounds, which are considered inorganic). It includes all information in scientific journals, but patents, conference reports, and disserta- tions generally were not reviewed. The volumes published so far are listed on p. V/' Organometallic compounds are classified according to their nuclearity and the bonding mode of the organic ligands nL. Nuclearity means the number of atoms of the title metal in the formula unit disregarding any additional metals that may be present. The term nL designates a ligand bonded by n carbon atoms to one or different atoms of the title metal. As usual, a-bonded 1 L ligands are designated by R. Inorganic ligands (Le., ligands bonded exclusively by elements other than carbon) are generally designated by 0 or X. 0 means donor ligands such as pyridine or phosphanes; m-electron donors are specified by mO. X is reserved for negatively charged ligands or other one-electron donors such as halogens or SnR; bridging X ligands may donate one 3 2 2 2 (~-H), three (~-Cl, ~-OR), or five (~3-1) electrons. Terms such as lL_ 0, 20-X, or 20_ 0_ 0 may be used for multidentate ligands. Heterometals are often designated by M, and bridging elements, bridging groups, or nonmetallic cluster constituents by E. The symbols 1] and ~ follow the IUPAC nomenclature.