Complexation halate

The modes of thermal decomposition of the halates and their complex oxidation-reduction chemistry reflect the interplay of both thermodynamic and kinetic factors. On the one hand, thermodynamically feasible reactions may be sluggish, whilst, on the other, traces of catalyst may radically alter the course of the reaction. In general, for a given cation, thermal stability decreases in the sequence iodate > chlorate > bromate, but the mode and ease of decomposition can be substantially modified. For example, alkali metal chlorates decompose by disproportionation when fused ... 

Metal- and halogen-containing complexes (metal fulminates, halites, halates, etc.). 

The thermodynamic data for complexation of trivalent lanthanide and actinide cations with halate and haloacetate anions are reported. These data are analyzed for estimates of the relative amounts of inner (contact) and outer (solvent separated) sphere complexation. The halate data reflected increasing inner sphere character as the halic acid pKa increased. Use of a Born-type equation with the haloacetic acid pKa values allowed estimation of the effective charge of the carboxylate group. These values were, in turn, used to calculate the inner sphere stability constants with the M(III) ions. This analysis indicates increasing the inner sphere complexation with increasing pKa but relatively constant outer sphere complexation. 

Trivalent lanthanide and actinide cations form labile, ionic complexes of both inner and outer sphere character. Consequently, they are useful probes to study inner-outer sphere complexation competition due to ligand properties. Two earlier papers have reported complexation of these cations by two series of related anions, the halates (9) and the chloroacetates (10). In this paper we offer a more extensive analysis of the inner-outer sphere competition in these complexes. 

In summary, the halate data reaffirm the tendency of increased inner sphere character in Ln(III) complexes as the ligand pKa increases. 

Ring compounds with only three or four atoms (e.g., ethylene oxide) Metal- and halogen-containing complexes (metal fulminates halites, halates etc.)... 

The exchange between molecular halogen or hahdes and halates or perhalates is slow. The iodine-iodate-exchange reaction was investigated in detail by Myers and Kennedy (1950). The reaction is complex and a possible mechanism was proposed, which involves two-electron transfer from a chemical species containing I to one containing 102 as a rate determining step. 

Solomon IC, Halat TJ, El-Maghrabi R, O Neal MH, 3rd. Differential expression of connexin26 and connexin32 in the pre-Botzinger complex of neonatal and adult rat. J Comp Neurol 2001 440 12-19. 

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