Cations, monoatomic, stabilization

The Global HSAB Principle Stabilization of Endohedral Complexes of Cgo> Si60 and Ge60 with Monoatomic Cations and Anions... 

Born-Haber cycles have been used by Passmore et al. to rationalize the thermodynamic stability of a large number of AsF6 salts of cluster cations. The calculations correctly predict the stability of most characterized compounds and also give indications that some compounds, which never have been synthesized in spite of great efforts eg. AsFe salts of monoatomic halogen cations), are unstable. This success confirms the argument that the formation of sub-valent cations is mainly enthalpy driven and that a Coulombic treatment of their solid compounds often is a reasonable approximation. 

Table 1. Metal-molten salt systems in which solid, sub-valent compounds with metal-metal bonds have been synthesized by symproportionation or similar reactions. The many sub-halides of gallium and indium have been omitted. These compounds contain either sub-valent monoatomic cations e.Lj. (Ga )(GaCl4 )l > and (In )(Cl )] " and/or ligand-stabilized metal-metal bonded anions (Ga+)2(Ga2X6- ), X = Br, For a review of the sub-valent chemistry of the group...

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