Solid-state chemistry unit cells

Fig. 4.4 Crystal structures of two more 1 2 compounds oxygen is the larger circle in both (a) unit cell of rutile, Ti02l tetragonal, space group Pd1fmmr, (b) unit cell of 0-crKtobaiite, SiO, [From Ladd. M. F C. Structure and Bonding in Solid State Chemistry, Wiley ...

Fig. 4.5 Crystal structures ofjwo forms of ciilcium carbonate (a) unit cell of calcitc. rhombohedral. space group R3c (b) unit cel of aragonite, orthorhombic, space group Pcmn Circles in decreasing order of size are oxygen, calcium, and carbon. [From Ladd. M. F. C Structure and Bonduiy in Solid State Chemistry Wiley New York, 1979. Reproduced with permission.]...

A unit cell is a fundamental concept in solid state chemistry, and is the smallest repeating unit of the structure which carries all the information necessary to construct unambiguously an infinite lattice. 

Solid-state nuclear magnetic resonance (ssNMR) spectroscopy has emerged over the years as a powerful analytical method in solid-state chemistry, especially with the advancements in techniques that allow the acquisition of high-resolution spectra [47]. In the broadest sense, ssNMR is mostly applied in characterization of crystalline materials as a means to support PXRD structural analyses by providing information on the number of molecules in the asymmetric unit or the symmetry of the occupied positions within the unit cell. Another major field of application is the structural characterization of amorphous and disordered solids where standard X-ray diffraction-based techniques fail to give detailed structural information. When discussing ssNMR in the context of API polymorphism and synthesis of co-crystals,... 

Solid-state chemistry is based on the study of atoms that combine to build solid structures, or crystals. In Chapter 18, you learn how solid-state chemists describe the shape of crystal structures and how this determines the size and shape of the unit cell, which is then used to characterize the many different forms that solid structures take. For example ... 

The solid-state chemistry chapter uses color illustrations of crystalline unit cells and digital photos of models to clarify their structures. This edition features more archetypical unit cells and includes fundamental principles of X-ray crystallography and band theory. In addition, the ample amorphous-solids section has been expanded to include more details regarding zeolite syntheses, as well as ceramics classifications and their biomaterial applications. Sections on sol-gel techniques and cementitious materials also remain, which are largely left out of most solid-state textbooks. 

How good is this model of solid-state chemistry To demonstrate, we calculate the density of an element Hsted in Table 7.2 and compare our result with the known density. Take copper as an example. It assumes a cep structure, which means it has an fee unit cell. The accepted value for the metaUic radius of copper as found in Table 7.3 is 1.28 A. We know from our previous discussions that there are four copper... 

FIGURE 3.23. NaCl stmcture. (a) Unit cell contents of NaCl, shaded atoms represent Na, and unshaded Cl ions, (b) Edge-sharing octahedra in NaCl. (From West, A.R., Solid State Chemistry and Its Applications, John Wiley Sons, New York, 1984. With permission.)... 

Computational solid-state physics and chemistry are vibrant areas of research. The all-electron methods for high-accuracy electronic stnicture calculations mentioned in section B3.2.3.2 are in active development, and with PAW, an efficient new all-electron method has recently been introduced. Ever more powerfiil computers enable more detailed predictions on systems of increasing size. At the same time, new, more complex materials require methods that are able to describe their large unit cells and diverse atomic make-up. Here, the new orbital-free DFT method may lead the way. More powerful teclmiques are also necessary for the accurate treatment of surfaces and their interaction with atoms and, possibly complex, molecules. Combined with recent progress in embedding theory, these developments make possible increasingly sophisticated predictions of the quantum structural properties of solids and solid surfaces. 

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