Inert metal

Electrode processes are a class of heterogeneous chemical reaction that involves the transfer of charge across the interface between a solid and an adjacent solution phase, either in equilibrium or under partial or total kinetic control. A simple type of electrode reaction involves electron transfer between an inert metal electrode and an ion or molecule in solution. Oxidation of an electroactive species corresponds to the transfer of electrons from the solution phase to the electrode (anodic), whereas electron transfer in the opposite direction results in the reduction of the species (cathodic). Electron transfer is only possible when the electroactive material is within molecular distances of the electrode surface thus for a simple electrode reaction involving solution species of the fonn... 

Evidence of the organic nature of the substance may, be provided by the behaviour of the compound when heated on porcelain or platinum or other comparatively inert metal (e.g., nickel) the substance is inflammable, burns with a more or less smoky flame, chars and leaves a black residue consisting largely of carbon (compare Ignition Test above). 

Oxidation-reduction (redox) Inert metal (normally Pt but certain other metals can act in a similar manner) in a solution containing two species that give rise to a redox system. E depends on of the system and the relative activities of the oxidised and reduced forms. Quinone-hydroquinone QH4O2 -1- 2H+ -1- 2e-CjH4(OH)2, which is thus pH dependent Fe - -/Fe + Mn04-/Mn +... 

Substitution-inert metal ions as probes of biological function. J. I. Legg, Coord. Chem. Rev., 1978, 25,103-132 (84). 

Any inert metallic component of an electrode is written as the outermost component of that electrode in the cell diagram. For example, a hydrogen electrode constructed with platinum is denoted H+(aq) H2(g) Pt(s) when it is the right-hand electrode in a cell diagram and Pt(s) H2(g) H+(aq) when it is the left-hand electrode. An electrode consisting of a platinum wire dipping into a solution of iron(II) and iron(III) ions is denoted either Fe3+(aq),Fe2 (aq) Pt(s) or Pt(s) Fe3+(aq),Fe2+(aq). In this case, the oxidized and reduced species are both in the same phase, and so a comma rather than a line is used to separate them. Pairs of ions in solution are normally written in the order Ox,Red. 

Laboratory supply houses feature sink-mounted faucets heavily plated with inert metals for DI water. Less expensive plastic valves, available from plumbing supply houses, may be used as long as they contain no metal parts. Self-closing valves, while more expensive, will substantially reduce DI water consumption. 

Baranski AS, Fawcett WR, McDonald AC (1984) The mechanism of electrodeposition of cadmium sulphide on inert metals from dimethylsulphoxide solution. J Electroanal Chem 160 271-287... 

In volume 7 reactions of metallic salts, complexes and organometallic compounds are covered. Isomerisation and group transfer reactions of inert metal complexes and certain organometallics (not involving a change in oxidation state) are considered first, followed by oxidation-reduction processes (a) between different valency states of the same metallic element (b) between salts of different... 

The underlying problem in testing the validity of the additivity principle in corrosion, mineral extraction, and electroless plating is that the electrode metal itself forms part of one of the half-reactions involved, e.g., zinc in equation (5) and copper in equations (8) and (12). A much better test system is provided by the interaction of two couples at an inert metal electrode that does not form a chemical part of either couple. A good example is the heterogeneous catalysis by platinum or a similar inert metal of the reaction... 

Historically, indicator electrodes have been metals which form a redox couple with the analyte, such as a Ag electrode for the determination of Ag", or a chemically inert metal which responds to the activity ratio of a soluble redox couple, such as a Pt electrode for Fe /Fe. Whereas simple indicator electrodes of this type perform well for the analysis of relatively pure samples, they are often subjwt to interferen< when apphed to complex samples such as those of biological origin. 

Amperometry at inert metal cathodes is the most important approach to p02 measurements known today The subject of experimental investigations since 1945 the... 

Similar photovoltaic cells as those described above can be made with semiconductor/ liquid Junctions. The basic function of such a cell is illustrated in terms of an energy scheme in Fig. 2. The system consists of an n-type semiconductor and an inert metal... 

Oxidation- reduction An inert metal dips into a solution containing ions in two different oxidation states. An example consists of a platinum wire dipping into a solution containing ferrous and ferric ions. Such a cell is described by Pt Fe2 (c,). Fe3 (c2). The comma is used to separate the two chemical species which are in the same solution. These electrodes are similar to the gas electrodes, except that the two species involved in the electrode reaction are ions. The electrode reaction in the example is Fe3 + e Fe2, and there is the possibility of the electrode either donating or accepting electrons. 

A definite decomposition voltage occurs for the following reason. As soon as there is a potential difference between the electrodes, H+ ions move to the cathode and Cl ions to the anode. The ions are discharged, forming layers of adsorbed gas on the inert metal surfaces. This essentially amounts to having a hydrogen electrode and a chlorine electrode in place of the two platinum electrodes. The outcome is a typical chemical cell ... 

Many workers have tried to omit the mercury film by depositing the analyte directly on inert metals such as Pt, Au, Rh, Ir or Ag or on carbon materials such as glassy carbon or wax-impregnated graphite however, in general this was not successful (lack of selectivity for mixtures as a consequence of interdiffusion) and therefore it is rarely applied except for those nobler analyte metals that cannot be measured at mercury, such as Au, Ag and Hg itself. Nevertheless, metals such as Ni and Cr, which do not amalgamate, can be determined on an HMDE100. 

Oxidation-reduction electrodes. An inert metal (usually Pt, Au, or Hg) is immersed in a solution of two soluble oxidation forms of a substance. Equilibrium is established through electrons, whose concentration in solution is only hypothetical and whose electrochemical potential in solution is expressed in terms of the appropriate combination of the electrochemical potentials of the reduced and oxidized forms, which then correspond to a given energy level of the electrons in solution (cf. page 151). This type of electrode differs from electrodes of the first kind only in that both oxidation states can be present in variable concentrations, while, in electrodes of the first kind, one of the oxidation states is the electrode material (cf. Eqs 3.1.19 and 3.1.21). 

Oxidation-reduction electrodes, abbreviated to redox electrodes, consist of an inert metal (Pt, Au, Hg) immersed in a solution containing two forms... 

C) selective lability of coordination sites in complexes of this inherently inert metal offers synthetic... 

Faradaic Rectification Studies at Redox Couple/Inert Metal(s) Interfaces... 

Bipyridines were efficiently used in supramolecular chemistry [104], Since the molecule is symmetric no directed coupling procedure is possible. In addition, 2,2 6/,2//-terpyridine ligands can lead to several metal complexes, usually bis-complexes having octahedral coordination geometries [105,106], Lifetimes of the metal-polymeric ligand depend to a great extent on the metal ion used. Highly labile complexes as well as inert metal complexes have been reported. The latter case is very important since the complexes can be treated as conventional polymers, while the supramolecular interaction remains present as a dormant switch. 

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