“Organometallic thermochemistry is one of the growth areas in chemical investigation at the present time and has been so for thepast two decades. The thermochemist is now presented with an area for investigation almost unexplored, challenging his technical skills and beginning to be met." This remark was made by Henry Skinner at the second Rossini Lecture in 1978.1 Fourteen years earlier the same author wrote a similar comment in a review articleentitled The Strengths of Metal-to-Carbon Bonds, 2 which is the First comprehensive and critical survey of organometallic thermochemistry. Although this area of research had not experienced a fast growth during the 1960s and the 1970s, a result mainly of the experimental difficulties faced by thermochemists, the number of studies de-voted to organometallic complexes started to increase in the early 1970s, particularly after the groups of Wilkinson and Lappert independently reanalyzed the