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Molecular-arrangement structure

Based on molecular structure, arrange the binary compounds in order of increasing acid strength. Explain your choice. [Pg.748]

The various arrangements of carbon atoms can be categorised into senes , which describe a common molecular structure. The series are based on four main categories which refer to... [Pg.90]

Z-matriccs arc commonly used as input to quantum mechanical ab initio and serai-empirical) calculations as they properly describe the spatial arrangement of the atoms of a molecule. Note that there is no explicit information on the connectivity present in the Z-matrix, as there is, c.g., in a connection table, but quantum mechanics derives the bonding and non-bonding intramolecular interactions from the molecular electronic wavefunction, starting from atomic wavefiinctions and a crude 3D structure. In contrast to that, most of the molecular mechanics packages require the initial molecular geometry as 3D Cartesian coordinates plus the connection table, as they have to assign appropriate force constants and potentials to each atom and each bond in order to relax and optimi-/e the molecular structure. Furthermore, Cartesian coordinates are preferable to internal coordinates if the spatial situations of ensembles of different molecules have to be compared. Of course, both representations are interconvertible. [Pg.94]

Isotactic Type of polymeric molecular structure that contains sequences of regularly spaced asymmetric atoms that are arranged in similar configuration in the primary polymer chain. Materials having isotactic molecules are generally in a highly crystalline form. [Pg.153]

Computing the energy of a particular molecular structure (spatial arrangement of atoms or nuclei and electrons). Properties related to the energy may also be predicted by some methods. [Pg.3]

Figure 5.4 The molecular structure of basic beryllium acetate showing (a) the regular tetrahedral arrangement of 4 Be about the central oxygen and the octahedral arrangement of the 6 bridging acetate groups, and (b) the detailed dimensions of one of the six non-planar 6-membeted heterocycles. (The Be atoms are 24 pm above and below the plane of the acetate group.) The 2 oxygen atoms in each acetate group are equivalent. The central Be-O distances (166.6 pm) are very close to that in BeO itself (165 pm). Figure 5.4 The molecular structure of basic beryllium acetate showing (a) the regular tetrahedral arrangement of 4 Be about the central oxygen and the octahedral arrangement of the 6 bridging acetate groups, and (b) the detailed dimensions of one of the six non-planar 6-membeted heterocycles. (The Be atoms are 24 pm above and below the plane of the acetate group.) The 2 oxygen atoms in each acetate group are equivalent. The central Be-O distances (166.6 pm) are very close to that in BeO itself (165 pm).
How can there be so many compounds containing this one element The answer lies in the molecular structures. We shall find that carbon atoms have an exceptional tendency to form covalent bonds to other carbon atoms, forming long chains, branched chains, and rings of atoms. Each different atomic arrangement gives a mole-... [Pg.322]

Polycrystalline and well-oriented specimens of pure amylose have been trapped both in the A- and B-forms of starch, and their diffraction patterns84-85 are suitable for detailed structure analysis. Further, amylose can be regenerated in the presence of solvents or complexed with such molecules as alcohols, fatty acids, and iodine the molecular structures and crystalline arrangements in these materials are classified under V-amylose. When amylose complexes with alkali or such salts as KBr, the resulting structures86 are surprisingly far from those of V-amyloses. [Pg.340]

Whether they are called surfaces or interfaces, when the zones between parts of a structure are "thin"— from a fraction of a micrometer (the limit of the ordinary microscope) down to molecular dimensions—the matter in them assumes a character that is somewhat different from that seen when the same matter is in bulk form. This special character of a molecular population arranged as an interfacial zone is manifested in such phenomena as surface tension, surface electronic states, surface reactivity, and the ubiquitous phenomena of surface adsorption and segregation. And the stmcturing of multiple interfaces may be so fine that no part of the resulting material has properties characteristic of any bulk material the whole is exclusively made up of transition zones of one kind or another. [Pg.168]

The structural arrangement of group 11 amidinate complexes is determined by the substituents on the amidinate aryl groups as well as on the NCN carbon [14,19]. The electronic vs. steric effect of the substituents on the molecular arrangement of gold(I) amidinate complexes have been studied in detail in the Fackler laboratory. [Pg.3]


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See also in sourсe #XX -- [ Pg.632 , Pg.634 , Pg.661 ]




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Structural Arrangements

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