TO-BE situation

As in the alkanes, it is possible for carbon atoms to align themselves in different orders to form isomers. Not only is it possible for the carbon atoms to form branches which produce isomers, but it is also possible for the double bond to be situated between different carbon atoms in different compounds. This different position of the double bond also results in different structural formulas, which, of course, are isomers. Just as in the alkanes, isomers of the alkenes have different properties. The unsaturated hydrocarbons and their derivatives are more active chemically than the saturated hydrocarbons and their derivatives. 

Derive a relationship between the pressure difference recorded between the two orifices of a pitot tube and the velocity of flow of an incompressible fluid. A pitot tube is to be situated in a large circular duct in which fluid is in turbulent flow so that it gives a direct reading of the mean velocity in the duct. At what radius in the duct should it be located, if the radius of the duct is r l... 

Fig. 11. —Proposed Model for aTemary Complex between Heparin (HEP), Antithrombin (AT), and Thrombin (T), Involving an Octadecasaccharide Sequence of the Heparin Chain.419 [Within the large brace, full circles denote uronic acid residues, the small brace encompassing the minimal binding-site for AT. The thrombin-binding region is presumed to be situated towards the nonreducing end of the AT-binding sequence,933 which is arbitrarily assumed to be in the middle of the heparin chain.]...

It has often been assumed that atomic charges can be calculated from the measured dipole moment of a diatomic molecule and the bond length. For this assumption to hold, however, the center of negative charge of an atom would have to be situated at the nucleus, in other words, atoms would have to be spherical. But we have seen that atoms in molecules are not spherical, and so the center of negative charge is not centered at the nucleus. Each atom therefore has a dipole moment called the atomic dipole moment (Chapter 2). 

Simple resonance theory suggests that for 2-substituted selenophenes the selenium atom can be considered to be situated in an ortho position and the influence of mesomeric and inductive effects or chemical shifts should be parallel for the 3-carbon (cf. resonance formula 5-7 for a-I-M substituted derivative). 

From measurements of the dichroism of flow of amylose-iodine solutions,161 and from studies of the optical properties of crystalline amylose platelets and iodine-stained platelets,163 it was shown, following the suggestion of Hanes, that a helical configuration of the amylose in this complex is probable. This was later confirmed by x-ray measurements (see p. 378) the iodine atoms were shown to be situated in the core of helically-oriented amylose molecules. 

The silicate sheet in kaolinite, for example, has an 0-0 repeat distance in the sheet of 0.893 nm, whereas the octahedral or gibbsite sheet repeat is smaller, about 0.862 nm. Mismatch of the 1 1 sheets induces curvature with the smaller dimension sheet on the interior. The octahedral gibbsite layer in clays is postulated to be situated on the inside of the curve. This relationship contrasts with the hypothesis for chrysotile, in which the tetrahedral silicate sheet is smaller and is postulated to be the interior unit in the scrolled serpentine mineral. 

Structural information on 133 was provided by Kohler and coworkers who, in 1986, reported the isolation of its lithium salt and the determination of its crystal structure280. This structure showed the lithium cation to be situated on the endo surface of the anion and coordinated with both the allyl portion and the C(6)—C(7) double bond. Key internuclear distances of the anionic portion of the salt are summarized in Scheme 42. 

We were able to substitute the gem-methyls in the ketal ring with gem-phenyls. Compound 23 shows that this perturbation was quite harmful to both Reactions I and V. This result was unexpected since X-ray structure showed the gem-methyls to be well removed from the site of action (8) and one would expect gem-phenyls to be situated similarly. 

From rate and product studies with xylooligosaccharides it was concluded that a xylanase from Ceratocystis paradoxa requires a chain of at least five xylose residues for rapid binding and subsequent hydrolysis (18). The catalytic site is assumed to be situated asymmetrically within a row of the five binding subsites. Similar studies on a cellulase from Aspergillus niger also suggest the presence of five binding subsites (14). 

A microemulsion that has a high water content and is stable while in contact with a bulk oil phase, and in laboratory tube or bottle tests tends to be situated at the bottom of the tube, underneath the oil phase. For chlorinated organic liquids, which are denser than water, the oil is at the bottom phase rather than the top. See Microemulsion, Winsor-Type Emulsions. 

Fig. 2. The non-hydrogen framework of the H3Mn3(CO)i2 molecule (Ref. 18), as found prior to the location of the H atoms. The H atoms are believed to be situated in the equatorial plane in metal-metal bridging positions...

Fig. 4. The X-ray structure of H4Re4 (CO) 12 showing the non-hydrogen portion of the molecule (Ref. 12). Hydrogen atoms are believed to be situated in face-bridging positions...

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