Thermodynamic effects of crystal defects

The presence of defects means that almost all crystals are imperfect. The creation of a defect from an ideal crystal is 

At temperatures above OK, the thermodynamic balance favours the presence of defects, and the minimum value of AG is attained at a given equilibrium concentration of defects, the concentration being temperature-dependent. For example, bulk copper metal has around one vacancy for every lO atoms at 298 K, while at 1300 K one site in every 10 may be vacant. 

The following terms were introduced in this chapter. Do you know what they mean  

Housecroft and E.C. Constable (2010) Chemistry, 4th edn, Prentice Hall, Harlow - Chapters 8 and 9 give detailed accounts at an introductory level. 

Wells (1984) Structural Inorganic Chemistry, 5th edn, Clarendon Press, Oxford - Chapters 4 and 6 present careful descriptions, ranging from basic to more advanced material. 

At the beginning of this section we stated that almost all crystals are imperfect. The creation of a defect from an ideal crystal is an endothermic process, but is entropically favoured since a degree of disorder is introduced into the otherwise perfectly ordered lattice. The balance between the AJT and T/S.S terms (equation 28.2) is therefore important. 

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