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Proton ions and

Many researches have been concerned to identify the nature of the protonic ions and their configuration but the situation is not clear in general. A beautiful arrangement of atoms in the conduction plane of NH4 /H30 P"-alumina, as shown in Fig. 13.1, may be an exception. On the basis of this arrangement, Thomas Farrington discussed the reason for the unusually high conductivity of this crystal as follows the main hydrogen bonds are concerned with ions which makes it easy... [Pg.194]

It is possible to detemiine the equilibrium constant, K, for the bimolecular reaction involving gas-phase ions and neutral molecules in the ion source of a mass spectrometer [18]. These measurements have generally focused on tln-ee properties, proton affinity (or gas-phase basicity) [19, 20], gas-phase acidity [H] and solvation enthalpies (and free energies) [22, 23] ... [Pg.1343]

In an earlier section, measurements were described in which the equilibrium constant, K, for bimolecular reactions involving gas-phase ions and neutral molecules were detennined. Another method for detemiining the proton or other affinity of a molecule is the bracketing method [ ]. The principle of this approach is quite straightforward. Let us again take the case of a proton affinity detemiination as an example. In a reaction... [Pg.1358]

Covalent bonding, in all the cases so far quoted, produces molecules not ions, and enables us to explain the inability of the compounds formed to conduct electricity. Covalently bonded groups of atoms can, however, also be ions. When ammonia and hydrogen chloride are brought together in the gaseous state proton transfer occurs as follows ... [Pg.42]

An acid was once defined simply as a substance which produces hydrogen ions, or protons. However, the simple proton, H , is never found under ordinary conditions, and this definition required amendment. Bronsted and, independently, Lowry, therefore redefined an acid as a susbstance able to donate protons to other molecules or ions, and a base as a substance capable of accepting such protons. If we consider hydrogen chloride, HCl, as an example, the HCl molecule is essentially covalent, and hydrogen chloride (gas or liquid) contains no protons. But anhydrous hydrogen chloride in benzene will react with anhydrous ammonia ... [Pg.84]

Ionisations 2, 3 and 5 are complete ionisations so that in water HCI and HNO3 are completely ionised and H2SO4 is completely ionised as a monobasic acid. Since this is so, all these acids in water really exist as the solvated proton known as the hydrogen ion, and as far as their acid properties are concerned they are the same conjugate acid species (with different conjugate bases). Such acids are termed strong acids or more correctly strong acids in water. (In ethanol as solvent, equilibria such as 1 would be the result for all the acids quoted above.) Ionisations 4 and 6 do not proceed to completion... [Pg.85]

This reaction is due to the very strong basic property of the hydride ion H" which behaves as a powerful proton acceptor and is therefore strongly basic, i.e. [Pg.127]

Ammonia as a donor molecule. Because of the presence of the lone pair of electrons on the nitrogen atom, ammonia can behave as an electron pair donor. For example, ammonia abstracts a proton from a water molecule producing the tetrahedral ammonium, NH4, ion and forms the compounds HjN- AlClj and HjN- BClj. [Pg.217]

The role of the base is apparently primarily that of a proton remover from the reactive methylene group thus if B represents the base, reaction (i) gives the carbanion, which then combines with the positive carbon of the carbonyl group (reaction ii) the product regains a proton from the piperidinium ion, and then by loss of water followed by mono-decarboxylation of the malonic acid residue gives the final acid. [Pg.279]

A quantitative correlation between rate and equilibrium constants for the different metal ions is absent. The observed rate enhancements are a result of catalysis by the metal ions and are clearly not a result of protonation of the pyridyl group, since the pH s of all solutions were within the region where the rate constant is independent of the pH (Figure 2.1). [Pg.59]

Because water is not protonated in these solutions, its addition reduces the concentration of ions, and therefore the electrical conductivity. The conductivity reaches a minimum in solutions containing 97% of acid, but rises on further dilution as a result of the formation of nitrate and hydroxonium ions. ... [Pg.7]

NO3-] oc [N20J and so [NOai oc Now nitrate ions reduce the rate of formation of nitronium ion by de-protonating nitric acidium ions, and this effect must also depend upon [HN02]"toich> as was observed. [Pg.56]

The argtiments of Norman and his co-workers seem to give affirmative answers to the first and second of these questions, but it is doubtful if the available data further require such an answer for the third question. It can be argued that the crucial comparison made between the behaviour of benzyltrimethylammonium ion and protonated benzyl methyl ether is invalid, and that it is possible to interpret the results in terms of nitration by the nitronium ion, modified by protonation of the oxygen atom of the ether a case for the possible involvement of the nitro-nium ion in specific interaction leading to o-substitution has been made. ... [Pg.103]

The reaction corresponds to a proton transfer and not to a net formation of ions, and thus the AS is of minor importance in the whole series, especially for the two t-Bu derivatives. This last effect is believed to be due to a structure-promoting effect of the bulky alkyl groups in the disordered region outside the primary hydration sphere of the thiazolium ion (322). [Pg.93]

The stronger base is derived from the weaker conjugate acid Therefore add a proton to ammonia to give its conjugate acid (ammonium ion) and a proton to pyridine to give its conjugate acid (pyridimum ion) then look up the values for each... [Pg.38]

According to the Arrhenius definitions an acid ionizes m water to pro duce protons (H" ) and a base produces hydroxide ions (HO ) The strength of an acid is given by its equilibrium constant for ionization m aqueous solution... [Pg.49]

The proton transfer equilibrium that interconverts a carbonyl compound and its enol can be catalyzed by bases as well as by acids Figure 18 3 illustrates the roles of hydroxide ion and water m a base catalyzed enolization As m acid catalyzed enolization protons are transferred sequentially rather than m a single step First (step 1) the base abstracts a proton from the a carbon atom to yield an anion This anion is a resonance stabilized species Its negative charge is shared by the a carbon atom and the carbonyl oxygen... [Pg.763]

Proton transfers convert the ammonium ion and ethoxide ion to their stable forms under the reaction conditions... [Pg.858]

Step 6 Proton transfer processes yielding ammonium ion and the carboxylic acid ... [Pg.865]

Typical Cl processes in which neutral sample molecules (M) react with NH to give either (a) a protonated ion [M + HJ or (b) an adduct ion [M + NHJ+ the quasi-molecular ions are respectively 1 and 18 mass units greater than the true mass (M). In process (c), reagent ions (CjHf) abstract hydrogen, giving a quasi-molecular ion that is 1 mass unit less than M. [Pg.4]

Lasers can be used in either pulsed or continuous mode to desorb material from a sample, which can then be examined as such or mixed or dissolved in a matrix. The desorbed (ablated) material contains few or sometimes even no ions, and a second ionization step is frequently needed to improve the yield of ions. The most common methods of providing the second ionization use MALDI to give protonated molecular ions or a plasma torch to give atomic ions for isotope ratio measurement. By adjusting the laser s focus and power, laser desorption can be used for either depth or surface profiling. [Pg.12]

However, in both FI and FD, there are other neutral molecules on or close to the surface of the emitter and, in this region, ion/molecule reactions between an initial ion and a neutral (M(H)) can produce protonated molecular ions ([M + H]+), as seen in Equation 5.2. [Pg.26]


See other pages where Proton ions and is mentioned: [Pg.313]    [Pg.207]    [Pg.1544]    [Pg.476]    [Pg.785]    [Pg.139]    [Pg.11]    [Pg.2503]    [Pg.2166]    [Pg.1472]    [Pg.67]    [Pg.258]    [Pg.80]    [Pg.530]    [Pg.313]    [Pg.207]    [Pg.1544]    [Pg.476]    [Pg.785]    [Pg.139]    [Pg.11]    [Pg.2503]    [Pg.2166]    [Pg.1472]    [Pg.67]    [Pg.258]    [Pg.80]    [Pg.530]    [Pg.207]    [Pg.574]    [Pg.240]    [Pg.93]    [Pg.103]    [Pg.196]    [Pg.16]    [Pg.201]    [Pg.48]    [Pg.144]    [Pg.2]    [Pg.3]    [Pg.5]    [Pg.38]    [Pg.74]   
See also in sourсe #XX -- [ Pg.808 ]




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