Different geometrical arrangement

Isomers are substances having the same molecular formula and molecular weight, but differing in physical and chemical properties. Since branched and straight-chain alkanes with the same molecular formula can exist as distinct structures having different geometrical arrangement of the atoms, they are termed structural isomers. One example is C H,j (butane) which has two isomers ... 

Figure 4.7c-f summarizes a set of examples with different geometrical arrangements of point charges to elucidate some typical aspects of EFGs arising from symmetric or asymmetric charge distributions. 

Diagram of the relative energies of electrons in d orbitals for different geometric arrangements. 

Figure 6.6. Energy level diagram for exciton interaction with different geometric arrangements of molecules in a linear polymer.

Separation of EMCL and IMCL in proton muscle spectra is possible due to the different geometrical arrangement of these lipid compartments resulting in different bulk magnetic susceptibility (BMS). EMCL are nestled in long fatty septa along the muscle fibre bundles or fasciae, and can thus be described in a simplified way as coaxial cylinders. IMCL are located in a roughly spherical... 

Referring to or pertaining to a dependence of the properties of a molecular entity or a transition-state species in a particular electronic state on the relative nuclear geometry. Such effects are usually due to different geometrical arrangements. 

Figure 20 The stereochemistry of copper(II). Different geometric arrangements. The lower region shows the angles involved in converting a regular tetrahedron into a flattened tetrahedron, and then into square-planar geometry. From Reference 5.

The upheld shifts observed with cyclopropanes are probably related to their large observed magnetic susceptibilities,112 which is similar to that found for benzene. The different sense of the NMR shifts for benzene (downheld) and cyclopropane (upheld) is merely due to the different geometrical arrangement of the hydrogens in the two. The shift in benzene has been attributed... 

Figure 10.2 Different geometrical arrangements for the measurement of emission...

Different geometrical arrangements of the atoms attached to the central atom are possible for all coordination numbers greater than one. The coordination polyhedron (or polygon in planar molecules) may be denoted in the name by an affix called the polyhedral symbol. This descriptor clearly distinguishes isomers differing in the geometries of their coordination polyhedra. 

Figure 10.2 Different geometrical arrangements for the measurement of emission intensity (1) front surface (45 ) observation — A, (2) right angle (90°) observation — 6 (3) end-on (180°) observation — C.

Compounds that contain the same number of the same kinds of atoms in different geometric arrangements. 

As in any other chemical compound, different geometrical arrangements of substituent groups are possible in a polymer where rigid molecular units are involved. This gives rise to trans- and cis-configurational isomerism in polymers containing double bonds in their repeat units, as in polyacetylene and natural and synthetic rubbers. The structures of the trans- and m-isomers of polyacetylene and polybutadiene are illustrated in Fig. 1.8. 

The exciting and the Raman radiation may be absorbed by the sample or the solvent. The different geometrical arrangements are influenced differently,... 

The cyclo(ferra)trisiloxanes 3a,b and 4a are obtained as a mixture of two isomers, resulting from different geometrical arrangements of the ligands at the y-silicon and the iron, incorporated in the ring... 

Photolysis of 3-oxogibberellic acid in the solid state gives phenolic products whereas the methyl ester affords cyclobutane dimers. An A-ray analysis has revealed the different geometrical arrangements of the acid and the ester in the crystals which lead to this behaviour. A full paper describing the [2 + 2] photoaddi-... 

E. Hahne and U. Grigull [2.23] have compiled shape coefficients and shape factors for a large number of different geometrical arrangements and organised them systematically. A similar, extensive collection of shape factors for 45 different geometries is available in the VDI-Warmeatlas [2.24]. 

The maximum packing volume of a filler can be calculated for different geometrical arrangements, determined after the filler is dispersed in a liquid media (e.g. oil). It is calculated by dividing the tamped bulk density by specific gravity of filler. Table 5.8 compares the data obtained from calculation for monodispersed spheres in different arrangements with determined values. 

The higher form of the folds is largely determined by what amounts to another set of rules, which determine the way in which these two key secondary structural elements, helices and sheets, may be combined into higher-order motifs (Voet and Voet, 1995 Brandon and Tooze, 1999). In a helices, several rules explain the different geometric arrangements observed in native protein conformations. As Brandon and Tooze comment ... 

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