Which type of structure

The characteristic fruit and seeds of loco-weed are housed in which type of structure ... 

A second type of structural information can be deduced from the hyperfine splitting in EPR spectra. The origin of this splitting is closely related to the factors that cause spin-spin splitting in proton NMR spectra. Certain nuclei have a magnetic moment. Those which are of particular interest in organic chemistry include H, " N, F, and P. 

Certain molecular groupings are likely to introduce hazards into a process. The research chemist should identify groupings and molecular structures that may introduce these hazards. A search of the open literature will assist in identifying which types of compounds are likely to create potential hazards. Table 4.2 presents molecular structures and compound groupings associated with known hazards. The groupings in the table were developed from CCPS (1995d, Table 2.5), and Medard (1989). The table is not all-inclusive. 

Structural classifications of oxides recognize discrete molecular species and structures which are polymeric in one or more dimensions leading to chains, layers, and ultimately, to three-dimensional networks. Some typical examples are in Table 14.14 structural details are given elsewhere under each individual element. The type of structure adopted in any particular case depends (obviously) not only on the... 

Isoxazol-5-ones can exist in three different types of structures, cf. 45- 7 (R = H). Early investigators assigned structures to these compounds on the basis of unreliable chemical evidence thus the NH structure 47 was favored because the silver salt of 3-phenyl-isoxazol-5-one reacts with methyl iodide to give a product which was incorrectly (see reference 44) formulated as the iV-incthyl derivatives (cf. also reference 46). Bromine titration data led to assignment of an incorrect structure to 3,4-diphcnylisoxazol-5-one cf. article I (Volume 1), Section II,A. Comparison of the dipole moments of 3-phenyIisoxazol-5-one with those of the methyl derivatives 45 (R = Me) and 46... 

Care must be taken regarding the method of supporting ceiling panels. Large portal framed steel holdings may provide a cheap outer shell but do have a considerable amount of roof movement. Panels hung from this type of structure can be subjected to movement which cannot be tolerated in cold store construction. A tied portal, however, can be acceptable [38]. The outer shell may also be required to bear the weight of the evaporators and, in the case of stores for carcase meats, the rails and the product itself. 

Senegas and Galy obtained the same type of structure for Ni2Nb03F3, while investigating solid solutions in a NiF2 - NiNb2C>6 system [263]. Niobium and nickel cations are randomly located in the oxyfluoride octahedrons, which are linked via their sides. 

Oxyfluoroniobates, M2Nb05F, containing trivalent metals (where M = Ti, V, Cr) have the same type of structure [264], except for Cr2Nb05F, which has a tri-rutile type structure. This exception is related to the ordered, rather than statistical, distribution of chromium and niobium cations in the oxyfluoride octahedrons, which leads to a corresponding increase in cell parameter c. 

After the possible structures are obtained, predict their mass spectra by examining the mass spectra of similar structures. Also, the GC retention time may eliminate certain structures or isomers. Discuss these results with the originator of the sample to determine the most probable structure. With experience, it is usually possible to determine which fragment peaks are reasonable for a given type of structure. 

There is another type of bifurcation called Turing bifurcation, which results in a spatial pattern rather than oscillation. A typical example where a new spatial structure emerges from a spatially unique situation is Benard s convection cells. These have been well examined and are formed with increasing heat conduction.53 Prigogine called this type of structure a dissipative structure.54-56... 

Linkage isomerism This is a special type of structural isomerism in which the differences arise from a particular ligand which may coordinate to a metal ion in more than one way. In Table 1-3 we indicated that a ligand such as thiocyanate could bond to a metal through either the nitrogen or the sulfur atom, and the complex ions [Co(NH3)5(ACS)]2+ and [Co(NH3)5(5CN)]2+ are related as linkage isomers. 

Although the bonding of many compounds can be adequately described by a single Lewis structure (p. 12), this is not sufficient for many other compounds. These compounds contain one or more bonding orbitals that are not restricted to two atoms, but that are spread out over three or more. Such bonding is said to be delocalized. In this chapter, we shall see which types of compounds must be represented in this way. 

The structures shown in Figure A.l are those received by ordinary computer terminals. Better looking structures, more like those printed in books, are obtained with certain types of terminals. The system always asks the user to specify which type of terminal is being used. 

The classical view of the lone pair is that, after mixing of the s and p orbitals on the heavy metal cation, the lone pair occupies an inert orbital in the ligand sphere [6]. This pair of electrons is considered chemically inert but stereochemi-cally active [7]. However, this implies that the lone pair would always and in any (chemical) environment be stereochemically active, which is not the case. For example, TIF [8] adopts a structure, which can be considered as a NaCl type of structure which is distorted by a stereochemically active lone pair on thallium. In contrast TlCl [9] and TlBr [10] adopt the undistorted CsCl type of structure at ambient temperature, and at lower temperatures the (again undistorted) NaCl type of structure. The structure of PbO [11] is clearly characterized by the stereochemically active lone pair. In all the other 1 1 compounds of lead with... 

Thallous halides offer a unique possibility of studying the stereochemistry of the (chemically) inert electron pair, since their structures and their pressure and temperature-dependent phase transitions have been well established. Thallium (1) fluoride under ambient conditions, adopts an orthorhombic structure in the space group Pbcm which can be regarded as a distorted rocksalt structure (Fig. 2.4). In contrast to TIF, the thallium halides with heavier halogens, TlCl, TlBr and Til, adopt the highly symmetric cubic CsCl structure type under ambient conditions [46]. Both TlCl and TlBr, at lower temperatures, undergo phase transitions to the NaCl type of structure [47]. 

Prl3 (PuBr3-type of structure, for Lal3 d = 334pm (6x), 340 pm (2x) [21]). Pr2ls is a semiconductor which orders antiferromagnetically below Tn = 37(1) K [19,... 

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