Halic acids and halates

These acids, having the formula (HO)aXO with b = 2, are strong acids, but HC103 and HBr03 exist only as aqueous solutions. The X03 anions have 26 electrons, leading to the C3v structure 

The acids are obtained by several reactions including the following  

Commercially, electrolysis of a solution of NaCl is used to prepare NaC103  

The acids HC103 and HBr03 decompose when heated, and the disproportionation reaction of HC103 produces the perchlorate  

However, in the case of HBr03 decomposition occurs as shown in the following equation  

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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. 

All the halic acids are strong acids and arc powerful oxidizing agents the mechanisms of reduction, e.g., by I- are very complicated.2 11 The halate ions, XO3, are all pyramidal, as is to be expected from the presence of an octet, with one unshared pair, in the halogen valence shell. 

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