ioniccond_lect26

Na cl cl na cl na cl e to get across the unit cell

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Unformatted text preview: leading to no net ionic migration. Na Cl Cl Na Cl Na Cl E To get across the unit cell into the vacancy the Na+ ion must hop through the center of the cube where it squeezes by 4 Cl- and 2 Na+. The energy of this "transition state" will determine the ease - Solid State Chemistry Chem 754 of migration. 3 Ion Migration (Frenkel Defects) The Frenkel defects in AgCl can migrate via two mechanisms. Ag Cl Ag1 Cl Ag Cl Ag2 Ag Cl Ag Ag Cl Cl Ag Ag Cl Cl Cl Ag Ag1 Ag2 Ag Cl Cl Cl Ag Direct Interstitial Jump Ag Cl Ag1 Cl Ag Cl Ag2 Ag Cl Ag Ag Cl Cl Ag Ag Cl Cl Cl Ag Ag2 Ag1 Ag Cl Cl Cl Ag Interstitialcy Mechanism Chem 754 - Solid State Chemistry Applications of Ionic Conductors There are numerous practical applications, all based on electochemical cells, where ionic conductivity is needed and it is advantageous/necessary to use solids for all components. Batteries e- Useful Power Fuel Cells Gas Sensors Electrolyte Anode Cathode In such cells ionic conductors are needed for either the electrodes, the electrolyte or both. Electrolyte (Material needs to be an electrical insulator to prevent short circuit) Electrode (Mixed ionic and electronic conductivity is needed to avoid open circuit) Chem 754 - Solid State Chemistry 4 Schematic of a Solid Oxide Fuel Cell Chem 754 - Solid Stat...
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This note was uploaded on 06/11/2011 for the course CHEM 101 taught by Professor Stegemiller during the Spring '07 term at Ohio State.

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