Selected standard reduction potentials

Table 4. Standard Reduction Potentials for Selected Manganese Compounds...

Preparation and chemistry of chromium compounds can be found ia several standard reference books and advanced texts (7,11,12,14). Standard reduction potentials for select chromium species are given ia Table 2 whereas Table 3 is a summary of hydrolysis, complex formation, or other equilibrium constants for oxidation states II, III, and VI. 

The potential measured in this way is called the standard reduction potential. A selection of standard reduction potentials is given in Table 2.6. 

E° values have been measured for many reactions and tabulated as standard half-cell potentials. Table 9.3 summarizes half-cell potentials as standard reduction potentials for a select set of reactions.aa In the tabulations, E° for... 

This technique allows the selective electro-deposition of a metal from a solution in the presence of ions of a less noble metal, provided that there is a sufficient difference between their standard reduction potentials the latter condition suggests remaining on the safe side (less negative) with the cathodic potential, so that the analysis may lose much in velocity on the other hand, the simplicity of procedure and apparatus is an advantage. 

The selectivity of RNH2 on M/A1203 and Raney catalysts decreased in the order Co Ni Ru>Rh>Pd>Pt. This order corresponds to the opposite sequence of reducibility of metal-oxides [8] and standard reduction potentials of metalions [9], The difference between Group VIII metals in selectivity to amines can probably been explained by the difference in the electronic properties of d-bands of metals [3], It is interacting to note that the formation of secondary amine, i.e. the nucleophilic addition of primary amine on the intermediate imine can also take place on the Group VIII metal itself. Therefore, the properties of the metal d-band could affect the reactivity of the imine and its interaction with the amine. One could expect that an electron enrichment of the metal d-band will decrease the electron donation from the unsaturated -C=NH system, and the nucleophilic attack at the C atom by the amine [3], Correlation between selectivity of metals in nitrile hydrogenation and their electronic properties will be published elsewhere. 

Practically in every general chemistry textbook, one can find a table presenting the Standard (Reduction) Potentials in aqueous solution at 25 °C, sometimes in two parts, indicating the reaction condition acidic solution and basic solution. In most cases, there is another table titled Standard Chemical Thermodynamic Properties (or Selected Thermodynamic Values). The former table is referred to in a chapter devoted to Electrochemistry (or Oxidation - Reduction Reactions), while a reference to the latter one can be found in a chapter dealing with Chemical Thermodynamics (or Chemical Equilibria). It is seldom indicated that the two types of tables contain redundant information since the standard potential values of a cell reaction ( n) can be calculated from the standard molar free (Gibbs) energy change (AG" for the same reaction with a simple relationship... 

Table A5.6 gives selected values for standard reduction potentials at T = 298.15 K. The values were taken from W. M. Latimer, The Oxidation States of the Elements and their Potentials in Aqueous Solutions, Second Edition, Prentice-Hall, Inc., Engelwood Cliffs, N.J. (1952).

The electrochemical behavior of the A-D compounds (selected structures are shown in Fig. 16) agrees well with that expected on the basis of the electrochemical properties of both the donor and the acceptor moieties [134-138]. That they can be reversibly reduced and oxidized to the corresponding radical cation and anion has been ascertained by cyclic voltammetry. The standard reduction potentials, are close to the values found for the parent aromatic hydrocarbons or acridine [124]. In a similar way, the standard oxidation potentials, °, are congruent with those found for the corresponding amines [148]. The electrochemical reaction of A-D compounds can be formulated as follows ... 

Standard Reduction Potential for Selected Half-Cells... 

Selected values of standard reduction potentials are listed in Table 7.1 (see also Appendix 11). Most of these values have been obtained directly from potential difference measurements, but a few values have been calculated from data obtained by calorimetric methods. This latter technique is for systems that cannot be investigated in aqueous media because of solvent decomposition (e.g. F2/2F ) or for which equilibrium is established only very slowly, such that the electrode is non-reversible (e.g. O2, 4H /2H20). Table... 

Table 7.1 Selected standard reduction potentials (at 298 K) further data are listed in Appendix 11. The concentration of each substance in aqueous solution is Imoldm and the pressure of a gaseous component is 1 bar (10 Pa). Note that where the halfcell contains [OH] , the value of E° refers to [OH ] = Imoldm , and the notation °[oh-] = i should be used (see Box 7.1).

Table 8.5 Selected standard reduction potentials (298 K) in aqueous and liquid ammonia media the concentration of each solution is 1 moldm. The value of E° — 0.00 V for the H / H2 couple is defined by convention.

Equation (5) or (11) can be applied directly to half-cell reactions such as (6) and (7) and the resulting potentials obtained will be identical to those obtained from the overall reactions (9) and (10) because of the definition of the SHE as the universal standard. A selection of standard potentials of half-cell reactions is shown in Table 1 [5]. By international convention, electrode reactions in thermodynamic tables are always written as reduction reactions, so the more noble metals have a positive standard potential. Lists such as that in Table 1 are also called electromotive force series or tables of standard reduction potentials. 

Table 4.7 Standard reduction potentials (in V) of selected half-reactions in the aqueous H Oy system (Milazzo and Carol 1978, Bard et al. 1985, Stanbury 1989, Wardman 1989, Holze 2007), at 25 °C. e electron transferred from electrode, hydrated electron, (g) gase-ons, aq) dissolved.

Table 1. Relationship Between Standard Reduction Potential (E ) and the Mechanism of Methylation for Selected Elements...

TABLE 5.11 Standard reduction potentials for selected elements at 25 °C. 

Perhaps not surprisingly, there is also a connection between the HSAB properties of ions and their redox properties. For example, the noble metals, those that are resistant to corrosion or oxidation in air, are all derived from soft-acid cations (Ru, Rh, Pd, Ag, Os, Ir, Pt, Au, and Hg). In fact, Pd, Pt, Au, and Hg can only be dissolved in aqua regia (or king s water ), which is a I 3 (v v) mixture of concentrated HNO3 with HCI. The ° values for selected noble metals are listed in Table 14.12. As expected, these metals have very positive standard reduction potentials. For comparison, the standard reduction potentials for a variety of other materials were already presented in Table 5.1 I. 

TABLE 14.12 Standard reduction potentials for selected ions of the noble metals. 

---