Clusters Including Hydrogen Atoms

Release of silyl radicals and Tl-Tl bond formation may open the access to 61. The Tl-Tl distances in 61 are relatively short (285 to 298 pm) and correspond to values observed in tetraorganyldithallanes R2TI-TIR2. Accordingly, the electron count gives ten electrons available for metal-metal interactions, and the bonding in the cluster may thus be described by five Tl-Tl single bonds. 

Shlykov, H. V. Volden, C. Dohmeier, H. Schnockel, Organo-metallics, 1995, 14, 3116-3119 A. Haaiand, K.-G. Martinsen, H. V. Volden, D. Loos, H. Schnockel, 

Inorganic Chemistry Highlights, G. Meyer, D. Naumann, L. Wese-mann, eds., Wiley-VCH, Weinheim, 2002, pp. 229-243. 

Stasch, M. Ferbinteanu, J. Prust, W. Zheng, F. Cimpoesu, H. W. Roesky, J. Magull, H.-G. Schmidt, 

Haiduc, D. B. Sowerby, eds., The Chemistry of Inorganic Homo- and Heterocycles, Academic Press, London, 1987. 

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Covalent. Formed by most of the non-metals and transition metals. This class includes such diverse compounds as methane, CH4 and iron carbonyl hydride, H2Fe(CO)4. In many compounds the hydrogen atoms act as bridges. Where there are more than one hydride sites there is often hydrogen exchange between the sites. Hydrogens may be inside metal clusters. 

The representation of an essentially infinite framework by a finite SCF treated cluster of atoms, (with or without point-ions), inevitably leads to the problem of how to truncate the model-molecule . Previous attempts at this have included using hydrogen atoms l and ghost atoms . Other possibilities include leaving the electron from the broken bond in an open shell, or closing this shell to form an ionic cluster. A series of calculations were performed to test which was the host physically realistic, and computationally viable, solution to this problem for this system. 

Figure 5. Two Moi54 clusters can be held to each other through a water network involving two pentagonal boxes (one associated with each (Mo)Mo5), each with five hydrogen bonded links (as Figure 4b) plus four further hydrogen bonded links from each of the local (Mo)Mo5Mo5C>33 clusters and associated links from neighboring clusters and including 45-plus shared molecules from the partial icosahedral water clusters. Water O-atoms are shown white with the Mo cluster atoms darker. The Mo—Mo distance between the two central surface Mo atoms of the Mo clusters is about 1.59 nm.

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