Crystal lattice defects

N. N. Greenwood, Ionic Crystals. Lattice Defects and Nonstoichiometry, Butterworths, London, 1968, 194 pp. 

For the spinel, Hercyanite, cissume that the cation changes in valence state. Then, draw a diagram illustrating the probable ion diffusion processes, give the diffusion conditions and the diffusion reactions, including the effect of induced crystal lattice defects. 

Figure 2 Crystal lattice defects of various dimensionalities. (Reprinted with permission from Ref. 5.)...

The majority of inorganic systems reported to exhibit photochromism are solids, examples being alkali and alkaline earth halides and oxides, titanates, mercuric chloride and silver halides.184 185 The coloration is generally believed to result from the trapping of electrons or holes by crystal lattice defects. Alternatively, if the sample crystal is doped with an impurity capable of existing in variable oxidation states (i.e. iron or molybdenum), an electron transfer mechanism is possible. 

N. N. Greenword, in Ionic Crystals Lattice Defects and Nonstoichiometry, Chemical Publishing, New York (1970). 

Howie, A., Whelan, M. J. (1962). Diffraction contrast of electron microscope images of crystal lattice defects. 111. Results and experimental confirmation of the dynamical theory of dislocation image contrast. Proc. Roy. Soc., (London), A267, 206-30. 

Glusker JP, Traeblood KN (1985) Crystal Stmctnre Analysis. 2nd edition. Oxford Univ Press, Oxford, UK Gnutzmaim V, Vogel W (1990) Surface oxidation and reduction of small platinum particles observed by in situ X-ray diffraction. Z PhysikD (Atoms, Molecules, Clusters) 12 597-600 Greenwood NN (1970) Ionic Crystals Lattice Defects and Norrstoichiometry. Butterworths, London Guinier A (1963) X-ray Diffraction in Crystals, Imperfect Crystals, and Amorphous Bodies. W H Freeman, San Francisco... 

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