International Journal of Chemistry; Vol. 8, No. 1; 2016 ISSN 1916-9698 E-ISSN 1916-9701 Published by Canadian Center of Science and Education Generating Formulas of Transition Metal Carbonyl Clusters of Osmium, Rhodium and Rhenium Enos Masheija Rwantale Kiremire Correspondence: Enos Masheija Rwantale Kiremire, Department of Chemistry and Biochemistry, University of Namibia, Private Bag 13301, Windhoek, Namibia. E-mail:
[email protected] Received: December 14, 2015 Accepted: December 30, 2015 Online Published: January 21, 2016 doi:10.5539/ijc.v8n1p126 URL: http://dx.doi.org/10.5539/ijc.v8n1p126 Abstract The series for carbonyl clusters of transition metals have been developed. They may be considered to be formed with a fragment centered around the 14 electron valence content. The capping series are based on the fragment of 12 electron valence content. The formulas of clusters can be decomposed into series from which the shapes of clusters may be predicted. The electron counting numbers of carbonyl clusters can be identified. Keywords: Carbonyl and borane clusters, fragments, isolobal principle, numerical sequence of fragments, building blocks, cluster series, 14n and 4n rules, valence electron content, cluster number 1. Introduction The discovery of the first mono-skeletal transition metal carbonyl Ni(CO)4 one hundred and twenty five years ago (Mond, et al, 1890), opened a wide gate for the synthesis of hundreds of metal carbonyl complexes. The structure of the nickel carbonyl Ni(CO)4 at the time was proposed to be as shown in Figure 1(F-1) in which the nickel atom exerted a valence of 2 while the valence of carbon and oxygen were 4 and 2 respectively.