Hydronium perchlorate

This has been demonstrated in EQCM studies of PTh film redox switching in HC104 solutions of different concentration. Under conditions where thionine reduction is a 2e/3H+ process, electroneutrality alone predicts uptake of one anion (and three protons) per Th site a film mass increase of 102.5 g molTh"1, independent of solution composition. Experimentally, the mass change is less than 20 g mol 1 in 1 mol dm 3 HC104, decreases as the electrolyte is diluted, and even becomes negative at pH > 2 The variation of mass change with concentration is attributable to activity effects. Hydronium perchlorate is included within the film, to an extent dependent on polymer redox state and solution concentration. 

Nitric Acid. Anhyd perchloric ac reacts with 100% nitric ac to form nitronium perchlorate (02N C104 ) (see below) and hydronium perchlorate (see above under hydrates) (Ref 16) Ozone. Anhyd perchloric ac reacts with ozone when irradiated with light of wavelength 254my to give HOOCIO3, which is unstable and decomps to O Md chloric ac (Ref 25)... 

Perchloric acid, HC104 H20, is a colorless liquid made by distilling, under reduced pressure, a solution of a perchlorate to which sulfuric acid has been added. The perchloric acid distills as the monohydrate, and on cooling it forms crystals of the monohydrate. These crystals are isomorphous with ammonium perchlorate, NH4CIO4, and the substance is presumably hydronium perchlorate, (H30) + (C104) . ... 

Solvent potential. The averaged solvent electrostatic field, , is important for inhomogeneous media, such as enzymes, membranes, miscelles and crystalline environments systems. Due to the existence of strong correlations, such a field does not cancel out. This factor becomes an important contribution to solvent effects at a microscopic level. In a study of non-rigid molecules in solution, Sese et al. [25] constructed a by using the solute-solvent atom-atom radial distribution function. Electrostatic interactions in three-dimensional solids were treated by Angyan and Silvi [26] in their self-consistent Madelung potential approach such a procedure can be traced back to a calculation of . An earlier application of the ISCRF theory to the study of proton mechanisms in crystals of hydronium perchlorate both [Pg.441]

Hydronium ion, HjO+, is a structural unit in solid perchloric acid hydrate, HCKVHjO, as shown by nuclear magnetic resonance studies. 

Let us now extend the long-period hydronium ice-like model for the IHP on Pt(lll) to explain the observations in electrolytes other than sulphate. In acid chloride, both the observations and the model carry-over directly from the case of sulphate. In fluoride, perchlorate, bicarbonate and hydroxide, in Which the anomalous features shift considerably in both potential and appearance (especially in the basic media) from sulphate, another model is needed. Both (bi)sulphate and chloride are large weakly hydrated anions, and in the double-layer model of Figures 4-5, they interact strongly with both the hydronium ions and the Pt surface. The contact adsorption... 

It is certain that the proton does not exist by itself in water. The simplest formula found in some crystalline salts is H30+. For example, crystals of perchloric acid monohydrate contain pyramidal hydronium (also called hydroxonium) ions ... 

A number of hydrates of perchloric acid, HCICV/zfyO. where n = 1, 2, 2.5, 3, and 3.5. are known. These are commonly referred to as the hydronium or oxonium perchlorates, H O+CIO", because of the analogy between the x-ray patterns of these species and ammonium perchlorate. 

Fia. 5. Reaction rates in concentrated perchloric acid as a function of Ha. The circles are the experimentally obtained rate data. The dashed lines represent unit correlations with the hydronium ion concentration, while the solid lines represent unit correlations with Ho. (a) Methylmercuric iodide cleavage at 100° (Kreevoy, 1957). (b) Cyclopropyl-mercuric iodide cleavage at 25° (Kreevoy and Thoreen, unpublished results), (c) Vinyl-mercuric iodide cleavage at 25° (Kreevoy and Kretchmer, 1964). 

In solution, the nature of the protonation agent affects the site of protonation of enamines267-269. The hard hydronium ion, such as is formed in 70% perchloric acid, initially leads at low temperature to the kinetically favoured N protonation, whereas the softer carboxylic acids, where the proton is situated on an uncharged oxygen, preferentially attack the softer base site, namely the /7-carbon atom, leading to C protonation and hence to the thermodynamically favoured product. 

A third conclusion to be drawn from the equilibrium represented by equation (3) is that since the solvent S is to be regarded as a base, the corresponding hydrogen ion SH+ is an acid. The hydronium ion H3O+ is thus an acid, and in fact the acidity of the strong acids, e.g., perchloric,... 

In solution, the nature of the protonation agent affects the site of protonation of. The hard hydronium ion, such as is formed in 70% perchloric acid. 

Special consideration should be given to the results in perchloric acid solutions. These were chosen because C104" anions do not chemically interact with molecular and radical products of water radiolysis (2). It excluded accessory effects and let us investigate reaction kinetics with the H30+ ion. The results which were obtained were unexpected. As shown in Table I, the value of observed rate constant is constant and independent of hydronium ion concentration over two orders of magnitude. 

Thus, the results from perchloric acid solutions show that the kinetics do not change when the concentration of HC104 varies. The rate of the spectral decay obeys the first-order reaction law. Calculated rate constants coincide when perchloric acid solutions and pure water are used. It can likely be explained that the intermediates which arose under irradiation do not interact with hydronium ions. Obviously, it is rather difficult to understand the results in view of the accepted theory of the hydrated electron. 

Coon et al. [58] have reported the preparation of aftronium trifluoro-methane sulfonate based on the analogy of the related preparation of the perchlorate or fluoroborate. Hydronium trifluoromethanesulfonate is, however, difficult to separate from the nitronium salt... 

Kreevoy studied in depth the deoxymercuration of CH3CH(OR)CH2HgI with perchloric and acetic acids in methanol, and found that the process was pseudo-first order in mercurial, with ka. [HA]. Specific hydronium ion catalysis was involved, and solvent HOH/DOD isotope effects were those predicted by the Butler equations for a pre-rate-determining proton transfer. Further studies on what had been termed - and /9-2-methoxy-cyclohexylmercuric iodides under similar conditions, led to similar findings concerning the solvent isotope effects, and correlation of log k with — Hq. This suggested that the transition state differs from substrate only by a proton. 

A striking example of a correlation between rate and the acid-base properties of the substrate is provided by recent work of Kresge on tritium exchange between hydronium ion and seven hydroxy- and alkoxy-benzenes. The basic strengths of these aromatic species can be determined by spectroscopic measurements in aqueous perchloric acid, and by com-... 

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