This is one of the first volumes to be published in the series of Chapman and Hall Chemistry Source books which provides carefully tailored information to workers in specialized areas of chemistry. The information contained in this book is derived from the Dictionary of Organometallic Compounds, published in November 1984. Organoruthenium and -osmium compounds constitute an important group of organometallics. They display a fascinating array of structural types, including a variety of cluster compounds, and they have uses as catalysts and reagents. Organoruthenium compounds in particular are widely used in catalytic processes. The varied properties of these compounds will ensure that this particular compendium will reach a wide readership. The databank on the properties of organometallic compounds, which is represented in its current form by the Dictionary of Organometallic Compounds and its subset publications such as this volume, will be kept continuously up-to-date. Supplements to the main Dictionary will appear annually and revised editions of this Sourcebook will be published from time to time as demands permits. G.R.Knox vii Introduction 1. Using the Sourcebook (2) Any compound with an established use, such as in catalysis, as a synthetic reagent or starting material. The Sourcebook is divided into element sections: (3) Other compounds of particular chemical, within each section the arrangement of entries is in structural, biological or historical interest, especially order of molecular formula according to the Hill those thought to exhibit unusual bonding characteris convention (i.e. C, then H, then other elements in tics.