Cluster compounds bond energy

Thermochemistry of cluster compounds. In this short summary of cluster structures and their bonding, a few remarks on their thermochemical behaviour are given, in view of a possible relationship with the intermetallic alloy properties. To this end we remember that for molecular compounds, as for several organic compounds, concepts such as bond energies and their relation to atomization energies and thermodynamic formation functions play an important role in the description of these compounds and their properties. A classical example is given by some binary hydrocarbon compounds. 

The relative weakness of the Sn - Cl bond in this case reflects a trend observed in all Group 14 compounds, in which bond dissociation energies (BDE) in a series MX n = 2-4) follow the order MX4 > MX3 and MX2 > MX3 [93]. For example, the bond energies in SnCU, SnCls, and SnCl2 are 84.2,42.9, and 91.1 kcalmoD based on our combined BAC-MP4 and coupled-cluster results. The relatively weak bond in SnCls makes the rate of Eq. 58 fast relative to Eq. 54, and thus not rate Hmiting. 

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