Solid-state structure

Solids are usually composed of atoms, molecules, or ions arranged in a rigid, repeating geometric pattern of particles known as a crystal lattice. Before looking at a variety of crystal lattices, we start this chapter with a survey of crystal types based on the nature of the forces among particles. 

The structures of the palladium dichloro compounds 4 a-c were determined by single-crystal X-ray analysis. Compounds 4a,c show disorder which could be resolved salisfaclorily. The expected bidentate coordination of the diimine nitrogen atoms to the Pd(II) center, forming square-planar (Fig. 2.6, 4a,b) and distorted square-planar (Fig. 2.6, 4 c) coordination environments, is found for all three complexes (Tab. 2.1). 

The phenyl rings in the 2,6-positions of the anihne rnoielies point towards each other above and below the N-Pd-N plane as a consequence of the specific location. In 4 a, the terphenyl units are not large enough to feel the steric influence of its symmetry-related counterpart, leading to a complex architecture that is nearly ideal C v-symrnelric. However, aheady here, the anihne-phenyl rings lack a free rotation around their N-C bond, as confirmed by variable temperature NMR ex- 

The cones defined by the t-angles can be regarded as an indication of the steric shielding of the metal center with respect to the virtual apical positions of the coordination polyhedron. The e-values are practically identical for 4a,b (Fig. 2.7 127.0°, 125.6°, respectively). Interestingly, e is significantly increased to 138.6° in 4 c. This effect is again attributed to the strong repulsive interaction between the 

The structure of solid HF consists of zigzag chains (Fig. 10.9a), although the positions of the H atoms are not accurately known. Hydrogen-bonded interactions persist in HF in both the liquid and vapour states (see Section 9.7). Structural parameters are available for a number of salts containing [HF2], and include neutron diffraction data for the deuterated species. The anion is linear with the H atom positioned symmetrically between the two F atoms (Fig. 10.9b). The H—F distance is relatively short, consistent with strong hydrogen bonding (see Table 10.4 and earlier discussion). 

Finally we come to the so-called dihydrogen bond. This is a weak electrostatic interaction that may occur between two 

The right-hand diagrams illustrate how complementary base pairs in adjacent strands in DNA interact through hydrogen bonding. (See also Fig. 10.16, p. 323.) 

No one detailed formulation for a given ion is appropriate in aU cases, and the environment and crystal packing of the [H(0H2) ]+ ions in a given solid state structure influence 

Vll Fig. 10.11 In the solid state structure of H3B-NH3, there are close contacts (202 pm), represented 

In describing the [H30] ion in Section 9.2, we also mentioned [11502] and [11904]. These latter species belong to a wider group of ions of general formula [H(H20) ]+. In solution, the formation of these ions is relevant to reactions involving proton transfer. Solid state studies, including neutron diffraction studies in which the positions of the H atoms are accurately determined, have provided structural data for the [H502]+, [HvOs]- , 904]+, [H 05]+ and 

4 Intermolecular hydrogen bonding in the solid state carboxylic acids 

Molecules containing carboxylic acid functionalities are not confined to organic systems. For example, the C=C double bond in fumaric acid can interact with a low oxidation state metal centre (see Chapter 23) to form organometallic compounds such as Fe(C0)4(r -H02CCHCHC02H) the T -prefix (see Box 18.1) indicates that the two carbon atoms of the C=C bond of the fumaric acid residue are linked to the Fe centre. Hydrogen bonding can occur between adjacent pairs of molecules as is depicted below, and such interactions extend through the solid state lattice to produce an extensive, three-dimensional array. 

In the solid state, the molecules are held together by hydrogen-bonded interactions to form sheets. These sheets interpenetrate to form a complex array containing channels part of the solid state lattice (determined by 

Moore and S. Lee (1994) Chemistry Industry, p. 556 - Crafting molecular based solids . 

Thermotropic LCPs are melt processed by injection molding and extrusion to form highly oriented rods, strands and molded articles. It is well known [348,364,365] that extrudates have high molecular orientation which develops as a result of the effect of the flow field on the easily oriented extended chain molecules. Molded articles composed of thermotropic LCPs have properties that are better than short fiber reinforced composites, and they have been termed 

Thermotropic LCP molded bars exhibit a layered structure as shown by reflected light (Fig. 5.79A) of a cut and polished bar. Thin sections of a molded bar show fine, nematic domains with superimposed flow lines (Fig. 5.79B, color section), especially near the center of the bar 

Complex skin-core and banded textures are observed in extrudates where the orientation is a function of the draw ratio and the final diameter, with higher orientation in finer strands. The orientation and incomplete extinction in the skin 

The common woody or fibrillar fracture of extrudates is clearly seen in the SEM micrograph in Fig. 5.82. This fracture morphology is controlled, to some extent, by the orientation of the strand. Micrographs of polished thin sections of an unoriented NTP rod (Fig. 5.83A, color section) and a slightly oriented rod (Fig. 5.83C, 

Etching experiments were also conducted in order to elucidate the fine structure of the NTP extrudates. Plasma etching of a polished extru-date was monitored by high resolution SEI. An overview (Fig. 5.84A) shows the flow lines of the 

Thermotropic LCPs are melt processed by injection molding and extrusion to form highly oriented rods, strands and molded articles. It is 

Thermotropic LCP molded bars exhibit a layered structure as shown by reflected light (Fig. 5.91A) of a cut and polished bar. Thin sections of a molded bar show fine, nematic domains with superimposed flow lines (Fig. 5.91B, color section), especially near the center of the bar (Fig. 5.91C, color section). Skin-core morphologies are obvious in injected molded bars and extrudates with domains aligned in the flow direction. Complementary SEM assessment of fractured injection molded bars provides an overall view of the layered structure (Fig. 5.92A), the surface skin (Fig. 5.92B) and the internal fibrillar structures of the inner skin (Fig. 5.92C) and core (Fig. 5.92D). 

Structural models describing LCP extrudates and moldings [429, 430, 453, 455, 459, 460] have been derived from microscopy techniques. Tha-par and Bevis [453, 455] showed a schematic of 

Thermotropic LCPs in the form of engineering resins are sold for molding into parts, such as interconnect devices. This requires high flow into the mold and high thermal stability to withstand post molding processes and end uses at elevated temperatures. The resins are sold as composites in extruded pellet form, compounded with fillers, such as glass fibers, carbon fibers, minerals and pigments. The product literature contains exten- 

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Siegbahn, K., Nordling, C., Fahlman, A., Nordberg, R., Hamerin, K., Hedman, J., Johansson, G., Bergmark, T., Karlsson, S.-E., Lindgren, I. and Lindberg, B. (1967) Electron Spectroscopy for Chemical Analysis Atomic, Molecular, and Solid State Structure Studies by Means of Electron Spectroscopy, Almqvist and Wiksells, Uppsala. 

K. A.tomic, Molecular, and Solid State Structure hj Means of Electron Spectroscopy, A xn.< s. 2iad S ks s J sA2L 1967. 

D. M. Adams, Inorganic Solids An Introduction to Concepts in Solid-State Structural Chemistry, Wiley, London, 1974, 336 pp. 

The solid state structure of 3-methyl- and 3-phenyl-4-hydroxy-2-oxo-2/7-pyrido[2,l-Z)]-[l,3]oxazinium inner salts were established by X-ray diffraction analysis (00JCS(P2)2096). The amide type N(5)-C(4)0 bonds are... 

The relative stereostructure of 9-acetyl-7-hydroxy-l,2-dimethyl-7-meth-oxycarbonyl-4-phenyl-6-oxo-l, 4,7,8-tetrahydro-6/7-pyrido[l, 2-u]pyri-midine-3-carboxylate 122 was justified by an X-ray diffraction analysis (97JOC3109). The stereochemistry and solid state structure of racemic trans-6,9-//-l, 6-dimethyl-9 z-ethoxy-9-hydroxy-4-oxo-l,6,7,8,9,9 z-hexahydro-4//-pyrido[l,2- z]pyrimidine-3-carboxylate (123), adopting a cw-fused conformation, were determined by X-ray investigations (97H(45)2175). 

The solid state structure of (3>S,8 Sj-10-(8-amino-6-azaspiro[3,4]octan-6-yl)-9-fluoro-3-methyl-7-oxo-2,3-dihydro-7//-pyrido[l,2,3-dfe]-l,4-benzoxa-zine-6-carboxylic acid (218) was determined by X-ray diffraction study (98CPB1710). The structure of 6,10-dihydropyrido[2,l-c][l,4]benzoxazine-6,10-dione 219 was established by X-ray diffraction analysis. It contains a crystal solvate with /j-xylene (99MI40). 

A transition-state structure was proposed on the basis of the solid-state structure of [Ni((R,R)-DBF0X)(H20)3](C104)2 (Fig. 1.8). The catalyst-dienophUe complex is thought to be a square-bipyramidal structure containing an octahedral nickel ion. The dienophile adopts an s-cis conformation with the si face shielded by a phenyl group. 

Hie solid-state structure of Cu2Li2Pb4iDMS) is closely related to tliat observ ed for Cu2Li2Pb4iOEt2)2, except tliat one of tlie litliium atoms bete is now four-coordinate as a result of coordination of two DMS molecides [114]. Hiis observation shows tliat even slight clianges in tlie coordinating properties of donor solvent molecules may cliange tlie overall structure of tlie cuprate. 

The solid-state structures of several benzylic carbanion salts have been elucidated by X-ray analysis9 depending on the nature of the benzylic part, the cation, and the additives, the structures range from er-bonded organometallic compounds to delocalized ion pairs, from monomeric to dimeric and polymeric aggregates. Some compounds are listed together with leading references ... 

Acetic add, ethylenediaminetetra-, 4,253 add-base equilibria, 2,779 in analysis, 1,522 complexes composition, 2,783 coordination numbers, 2,783 solid state structure, 2,783 cyclic derivatives complexes, 2,785 in electroplating, 6,14 heteroatom derivatives metal complexes, 2, 786 homologs... 

Although astronomy is accustomed to the detection of a few photons per pixel, the electric charge of a few electrons is extremely small. A critical part of the design of a focal plane array is the amplifier which converts the small amount of charge in each pixel into a signal that can be transmitted off the detector. The amplifier in an optical or infrared detectors is typically a field effect transistor (FET), a solid state structure which allows a very small amount... 

Miscellaneous TsRs, TsRyR, TsR6R 2. TsRsR j, and TsR4R 4 species 72 The solid-state structures of TsRs compounds 88... 

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