Lattice ionic crystals

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

X-ray crystallography of potassium, rubidium, and cesium methyls shows completely ionic crystal lattices Weiss, E. Sauermann, G. Chem. Ben, 1970, 103, 265 Weiss, E. Koster, H. Chem. Ber., 1977, 110, 717. 

The composition and properties of the ions contained in the solution are not the same as those of ions contained in the ionic crystal lattice. It is already known that anhydrous copper sulfate (CuS04) is colorless. This implies that Cu2+ and SCT ions that make up the crystal lattice of the sulfate are colorless. When the Cu2+ ions combine with water molecules during dissolution they turn blue (the color characteristic of copper salt). This color is therefore due to hydrated ions of copper, i.e., ions connected with the water molecules. 

In order to be able to describe the ideal crystal structure , it is important to bear in mind that there are two tetrahedral cavities and one octahedral one present for every sphere in a close-packed structure. With the help of Table 4.1 and the rules for octahedral and tetrahedral coordination the description of the following crystal structures are now easily understood when we bear in mind that in an ionic crystal lattice the larger negative ions form the close-packed structure and that the octahedral and tetrahedral cavities are filled with positive ions. 

Fig. 2 Conceptual illustration of a energy band scheme and b an ionic crystal lattice consisting of M2+ and O2- ions...

The quantity eoo represents the optical permittivity, which is determined by the electronic polarizability. The second term represents the ionic crystal lattice as a sum of N classical harmonic oscillators with eigenfrequencies ujj, damping constants Tj and oscillators strengths Sj. In order to fit Equation (5.7) to the observed far infrared spectra, these parameters are used... 

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

Apart from the difference in the bond energy, other criteria, both direct and indirect, exist between the two different types of bond. Ionic molecules in the solid state form an ionic crystal lattice which r.har ir,teristic lo he particular molecule In such a lattice, ea ion is surrounded by ions of opj site char at equal distances from the central ion and individual molecules cease to exist. The number of ions packed round the central ion is limited by the size of the ions, the attraction and repulsion energies between the ions and other factors. The links of the central ion with its nearest neighbours are all of the same strength and the number of such... 

Although metals do not bond ionically, they often form lattices in the solid state. These lattices are similar to the ionic crystal lattices that were discussed in Section 8.2. In such a lattice, eight to 12 other metal atoms surround each metal atom. Although metal atoms have at least one valence electron, they do not share these electrons with neighboring atoms nor do they lose electrons to form ions. 

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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