Nitrogen oxoanions

Rhenium(VI) complexes, 4,194 alkoxides, 4,196 amides, 4,194 amines, 4,199 carboxylates, 4,199 dimethylformamide, 4,199 dioxane, 4,198 halides, 4,195,199 2-hydroxypyridine, 4,199 imides, 4,194 magnetic behavior, 1,271 mixed sulfur-nitrogen compounds, 4,196 N heterocycles, 4,199 nitrides, 4,194 oxide halides, 4, 195 oxoanions,4,196 pyridine, 4,199 sulfates, 4,198 sulfur compounds, 4,196 tellurates, 4,198... 

Although the nonmetals do not readily form cations, many of them combine with oxygen to form polyatomic oxoanions. These anions have various stoichiometries, but there are some common patterns. Two second-row elements form oxoanions with three oxygen atoms carbon (four valence electrons) forms carbonate, C03, and nitrogen (five valence electrons) forms nitrate, NO3. In the third row, the most stable oxoanions contain four oxygen atoms Si04 -, P04 -, S04, and CI04. ... 

Fig. Structures of some oxides, oxocations and oxoanions of nitrogen.

Oxoanions usually have weak donor properties relative to water and nitrogen donors, and thus the properties of coordination complexes of these anions are extremely solvent dependent. For example, the CIO4 ion is generally considered to be a weakly coordinating anion in aqueous solution, and... 

This cationic Lewis acid can form complexes with the Lewis bases undergoing oxidation (species that are oxidizable are frequently electron rich and hence are Lewis basic). Therefore, at low pH the oxidant (NO" ) is a different chemical species than at higher pH (N02 ) (see Section 15.13(b) Nitrogen(IV) and mtrogen(IIl) oxides and oxoanions). 

Thus, the highest oxides or chromium(VI) and molybdenum(VI) were established to destroy molten KN03 with subsequent evolution of N02 termination of this destruction resulted in stabilization of the pO values of the melt [67], This value determined by the method of potentiometric titration was found to reduce as the temperature of the melt was elevated considerably. Such a behaviour of the acidic solution in the nitrate melt was explained by the formation of nitrogen pentoxide, N2Os, or nitronium cation, NOj, in the acidic solution, together with the corresponding oxoanions of Cr(VI) and Mo(VI). Since the added acids are very strong, their reaction with the melt... 

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