Defect notation

These equations represent expressions for the extrinsic ionic conductivity of the material as exhibited by the shortened defect notation of equation 12, showing that Na vacancies are created by doping and not primarily generated from thermal energy. 

Comparison of Point Defect Notation by Various Authors... 

Table 4.2 lists energy values assigned to point impurities such as Fe i i and Pqmi 111 the calculation of their energies, an ionization term necessary to subtract one electron from Fe + has also been added (ionization potential). With defect notation, this process can be expressed as... 

Nitrous oxide, or a gas with an analogous composition, is the anhydride of hyponitrous acid, H2N202, and could be called hyponitrous anhydride. Owing to our defective notation, it cannot be called nitrous anhydride by analogy with the nomenclature employed in many other cases. Nitrous anhydride, N203, is the anhydride of nitrous acid, HN02. To adjust the nomenclature, nitrous oxide would have to be called hyponitrous oxide. While the action of water on nitrous or hyponitrous anhydride does not form hyponitrous acid, yet the dehydration of hyponitrous acid by cone, sulphuric acid forms nitrous or hyponitrous oxide ... 

There are three possible thermally generated intrinsic disorder reactions in ceria that do not involve exchange with the gas phase. These defects, which are of the Schottky (Eq. 2.2) and Frenkel (Eqs. 2.3 and 2.4) types, can be represented using the Kroger and Vink defect notation, which will be used throughout this chapter ... 

Key aspects of the Kroger-Vink point defect notation are summarized in Table IR-11.1. 

Table IR-11.1 Examplesa of defect notation in M2+(X )2 containing a foreign ion Q...

Here we intended to study the DC conductivity, oxygen isotope exchange, andTPD techniques which give the active site information at the high temperature [10]. Two kinds of magnesia catalysts, i.e., MgO and Li/MgO were studi. The defect notations follow after Kroger [11]. 

Consider the addition of CaCl2 to NaCl. The Ca cation can substitute for a Na ion or go interstitial (needless to say, because of charge considerations, only cations will substitute for cations and only anions for anions). In the first case, the defect notation is Ca a, and the effective charge [+2 - (+1) = 1] is + 1. Conversely, an interstitial Ca ion is denoted as Ca. ... 

Figure 4.432. Reduced reaction set PDM used for interpreting the impedance of passive Alloy-22 in 6.2m NaCl + 0.001 m HCl (pH = 3) at 80°C. The defect notation is as given in Figure 4.4.29.

In the temperature region 1(T < Tc), the resistivity of PTC thermistor is in the range of 10-10 cm. To produce semiconductive BaTiOs, a small amount of rare earth metal ions (e.g. Sm + or La +) are substituted at the Ba + site, or Nb and Ta " " ions are substituted at the Ti site. These ions provide conductive electrons as shown in the following equations, using the defect notation of Kroger and Vink. 

Interstitial X ion DEFECT NOTATION effective negative charge... 

The concentration of conduction electrons or holes is in proportion to the mobile ionic defect concentration, i.e., n = zN or p = -zN where z is the effective charge of the mobile ionic species, in the sense of Kroger-Vink relative defect notation. High-electronic concentration MlECs. The electron or hole concentration is high and fixed, e.g., by doping of a semiconductor or in a metal MIEC. Then n NiOrp N. ... 

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