N2O5

Dinilrogen pentoxide, N2O5. White solid (HNO3 plus P2OJ) readily decomposes to NO2 and O2, sublimes 32-5 "C. In solid slate (N02) (N03) gaseous molecules O2NONO2... 

This is an acid-base reaction, in which the base is the oxide ion (p. 89) the acidic oxide SiOj displaces the weaker acidic oxide CO2 in the fused mixture. But in aqueous solution, where the 0 ion cannot function as a strong basefp. 89),carbon dioxide displaces silica, which, therefore, precipitates when the gas is passed through the aqueous silicate solution. In a fused mixture of silica and a nitrate or phosphate, the silica again displaces the weaker acidic oxides N2O5 and P4OJ0 ... 

HNO3-AcOH, 20 °C N2O5- ccu, 15 C Calc. HN03-25 °C Calc. 

Anhydrides. Anhydrides of inorganic acids are named as oxides for example, N2O5, dinitrogen pentaoxide. 

In contrast to the wealth of reactions in which N2O4 tends to behave as N0+N03, there is no evidence for reactions based on the alternative heterolytic dissociation N02" "N02". Earlier claims to have identified BF3 adducts such as [N02]+[0N0BF3] have been shown to be incorrect and the predominant products of the reaction of BF3 with N2O4 (and also with N2O3 and with N2O5) are, in fact, NO+Bp4 and N02+BF4". This latter compound had... 

N2O5 is the anhydride of nitric acid and is obtained as a highly reactive deliquescent, light-sensitive, colourless, crystalline solid by carefully dehydrating the concentrated acid with P4O10 at low temperatures ... 

X-ray diffraction studies show that solid N2O5 consists of an ionic array of linear NO2+ (N-O 115.4 pm) and planar NO3 (N-O 124 pm). In the gase phase and in solution (CCI4, CHCI3, OPCI3) the compound is molecular the structure is not well established but may be O2N-O-NO2 with a central N-O-N angle close to 180°. The molecular form can also be obtained in the solid phase by rapidly quenching the gas to — 180°, but it rapidly reverts to the more stable ionic form... 

N2O5 is readily hydrated to nitric acid and reacts with H2O2 to give pemitric acid as a coproduct ... 

In the gas phase, N2O5 decomposes according to a first-order rate law which can be explained by a dissociative equilibrium followed by rapid reaction according to the scheme... 

By contrast, Raman spectroscopy and conductivity measurements show that N2O4 ionizes almost completely in anhydrous HNO3 to give NO and NO3 and such solutions show no evidence for the species N2O4, NO2 or N02 N2O5 is... 

Under less-controlled conditions P4O10 dehydrates ethanol to ethene and methylai lcarbinols to the corresponding styrenes. H2SO4 is dehydrated to SO3, HNO3 gives N2O5 and amides... 

The reaction with HNO3 is quantitative, and the presence of large concentrations of the nitronium ion, NOi ", in solutions of HNO3, MNO3 and N2O5 in H2SO4 enable a detailed interpretation to be given of the nitration of aromatic hydrocarbons by these solutions. 

It is a yellow solid with an acyclic structure (Fig. 15.49a), cf N2O5 (p. 458). Moist air converts S3N2O2 to SO2 and S4N4 whereas SO3... 

Hydrolysis is slow at room temperature and the corresponding reaction with anhydrous HNO3 results in dehydration to the parent N2O5 ... 

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