INTERACTION OF ELECTRON SOURCES AND SINKS

A Correlation Matrix Displays All the Simple Interactions Between Two Groups 

Electron Flow In Organic Chemistry A Decision-Based Guide To Organic Mechanisms, Second Edition. 

By Paul H. Scudder Copyright 2013 John Wiley Sons, Inc. 213 

The flow of electron density, symbolized by a set of arrows, comes from the generic electron sources discussed in Chapter 5, via the pathways of Chapter 7, and ends in one of the generic electron sinks covered in Chapter 6. This chapter links common sources and sinks with appropriate pathways and discusses specific examples of each process. 

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It is helpful to summarize the appropriate use of key terms associated with arrow pushing and reaction mechanisms. The terms source and sink are used to identify the start and end, respectively, of each reaction mechanism arrow, which is indicating the change in location of electron pairs. The terms nucleophile and electrophile (as well as Lewis base and Lewis acid) are used to describe molecules based on their chemical reactivity and propensity to either donate or receive electrons when they interact. Protons can be thought of as a specific type of electrophile, and for reactions in which a proton is transferred, the nudeophile is called a base. 

In these time-dependent kinetic studies, a variety of electron collision processes similar to those treated in the steady-state kinetics has been treated. In addition to these processes, nonconservative electron collision processes, such as ionization and attachment, and even the nonlinear electron-electron interaction have been taken into accoimt. Besides the various types of electron collisions, other electron generation and destruction processes, such as the chemo-ionization in collisions between excited heavy particles in decaying plasmas or the injection of beamlike electrons into plasma, have been included as particle sources or sinks... 

All relevant electrochemical reactions in PEFCs exhibit peculiar sensitivities to the surface structure of the catalyst (Boudart, 1969). The abundances of the different surface sites, for example, edge sites, comer sites, or sites on crystalline facets, are related to the size of nanopartieles (Kinoshita, 1990). Support-particle interactions may alter the electronic stmeture of catalyst surface atoms at the rims with the support (Mukerjee, 2003). Moreover, the support may serve as a source or sink of reactants via the so-called spillover effect (Eikerling et al., 2003 Liu et al., 1999 Wang et al., 2010 Zhdanov and Kasemo, 2000). 

Electricity interacts with matter because electrons are part of matter and form the chemical bonds. When electrons are transferred from one molecule to the other we call it a redox reaction. Since electric current is the movement of electrons, micro electric currents then exist in the solution where redox reactions take place. If all these micro-currents were made to flow in one direction we should be able to measure them as one macro electric current. Batteries (which are also called galvanic cells or voltaic piles ) are devices which do exactly this they produce electric current by making redox reactions take place at electrodes, i.e. at the metal solution boundary. The metal can be either the source or the sink for electrons. Thus electric current is made to flow from the metal into the solution or from the solution into the metal. Can one do the reverse Can one induce redox reactions by passing through the solution current from a source The answer is definitely yes . The instrument by which such changes are produced is an electrolytic cell . A simple cell can be constructed from two pieces of dissimilar metals dipping into a solution of some electrolyte in a beaker. The metal pieces are now the electrodes. This book is concerned with chemical reactions produced by electric current or electric current produced by chemical reactions at electrodes. It is concerned with redox reactions in cells. 

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