Physical properties of crystals

N/A indicates the hardness value is above/below the acceptable range of the particular hardness scale. Values were obtained from the conversion site http //www.efunda.com/ units/hardness/convertJiardness.cfm HD=HM Cat=Steel ConvInto 

The intermolecular forces in a crystal lattice are often not homogeneous in all directions. If the solid consists of strong interactions among neighbors in specific layers, and weak interactions among molecules in neighboring layers e.g., graphite), 

In a previous section, we discussed substitutional impurities within crystal lattices without mentioning the changes in physical properties that this creates. Perhaps the most obvious outcome of a crystal impurity is the resultant color. In this section, we will answer the common question why are some crystals colorless, and others colored  

Colored crystals need not be gemstones in fact, a colorless crystal of potassium chloride may be suitably altered to exhibit color. When solid KCl is heated to 500°C in the presence of potassium vapor, the crystal becomes a violet color. This occurs due to the ionization of gaseous potassium atoms that abstract a Cl anion from the 

Another example of the coloration phenomenon is demonstrated by transition metal doping of crystals exhibited by gemstones such as ruby. Table 2.6 lists some common gemstones, and the respective host crystal and dopants that give rise to their characteristic colors. Whereas crystals of pure corundum (a-alumina) are colorless. 

What can we leaxn about the internal arrangement of atoms, ions, or molecules from the appearance and physical properties of a crystal The macroscopic physical properties of crystals are related to the arrangements of atoms within them. A careful examination of these physical properties leads to much useful information on the symmetry of the atomic arrangement, on the shape of the unit cell, and on the overall arrangement of molecules within the unit cell. Selected examples of such studies are described in this Chapter. 

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Nye, J.F. (1957) Physical Properties of Crystals (Clarendon Press, Oxford). 

International Tables for Crystallography, Vol. D Physical Properties of Crystals (A. Authier, ed.), Chapter 3.1 (J.-C. Toledano, V. Janovec, V. Kospky, J. F. Scott, P. Boek) Structural phase transitions. Kluwer, 2003. 

J. F. Nye, Physical Properties of Crystals Their Representation by Tensors and Matrices, Oxford University Press, Oxford, 1957. 

M. Catti, Physical Properties of Crystals in Elements of Crystallography, 2nd ed., C. Giacovazzo, H. L. Monaco, A. Artioli, D. Viterbo, G. Feriaris, G. Gilli. G. Zanotti, and M. Catti, Eds., Oxford University Press, Oxford, United Kingdom, 2002, Chapter 10. W. D. Kingery, H. K. Bowen, and D. R. Uhlmann, Introduction to Ceramics, 2nd ed., Wiley, New York, 1976. 

Type of Crystalline Solid Particles Involved Primary Forces of Attraction Between Particles Boiling Point Electrical Conductivity in Liquid State Other Physical Properties of Crystals Conditions Necessary for Formation Examples... 

Interaction of incident electrons with the electrostatic potential (ESP) gives the possibility to reconstmct the potential from transmission electron diffraction (ED) experiments. ESP and the electron density determine all physical properties of crystals (e.g. energy of electrostatic interaction, characteristics of the electrostatic field in crystals, dipole, quadmple and other momentum of nuclear, diamagnetic susceptibility. 

The physical properties of crystals depend on admixtures this is common knowledge. The admixtures can be present in a starting solution. Solvent molecules included in a crystal during its formation should be considered a contamination. In this sense, the highest attention should be... 

As for the physical properties of crystals, some account of crystal morphology and optics has been given in Chapters II and III, where, however, these subjects were developed only as far as was necessary for identification purposes. For structure determination further consideration of both these subjects, as well as others such as the magnetic, pyroelectric, and piezo-electric properties of crystals, is desirable this will be found in Chapter VIII. 

The effect of hydrogen bonds on the physical properties of crystals is shown in a striking way by oxalic acid. This substance exists in two anhydrous crystal forms. 1 One of these, the a form, contains layers of molecules held together by hydrogen bonds, the structure of a layer... 

Nye J. F., 1962, Wlasnoici fizyczne krysztalow w ujcciu tensorowym i macierzowym (Physical Properties of Crystals in Tensor and Matrix Approach), PWN, Warszawa. 

Physical Properties of Crystals , Oxford Univ Press, NY, (1956), 250pp 35)J-Krc, Jr,... 

In order to apply group theory to the physical properties of crystals, we need to study the transformation of tensor components under the symmetry operations of the crystal point group. These tensor components form bases for the irreducible repsensentations (IRs) of the point group, for example x, x2 x3 for 7(1) and the set of infinitesimal rotations Rx Ry Rz for 7(1 )ax. (It should be remarked that although there is no unique way of decomposing a finite rotation R( o n) into the product of three rotations about the coordinate axes, infinitesimal rotations do commute and the vector o n can be resolved uniquely... 

A similar procedure may be followed for other point groups and for tensors representing other physical properties of crystals. 

A new approach to the application of group theory in the study of the physical properties of crystals, which is more powerful than the direct method described in Section 15.2, has been developed by Nowick and is described fully in his book Crystal Properties via Group Theory (Nowick (1995)). A brief outline of Nowick s method will be given here. The equilibrium physical properties of crystals are described by constitutive relations which are Taylor expansions of some thermodynamic quantity Yt in terms of a set of thermodynamic variables Xj. Usually, only the first term is retained giving the linear relations... 

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