Chemical bonding terminal atom

Y represents an oxygen atom or a single chemical bond. In the case of diallyl ether double bond isomerization occurs to a considerably higher extent, easily reaching 20 - 30 mole percent [9]. Obviously, reactive terminal C=C double bonds are required to get fast reaction with hydrosiloxane crosslinkers, whereas isomeric inner double bonds exhibit too low a reactivity to be of importance. Another strategy may be helpful. 

The dodecahydrododecaborate anion, B H 2-, is termed unique with considerable justification. This ion and its perhalo derivatives, e.g., Bi2C1i22-, are the most symmetrical molecular aggregates known. The boron atoms occupy the vertices of a regular icosahedron and each is bonded terminally to a hydrogen atom all boron atoms are environmentally equivalent.7,8 This anion is the only known example of the 7 symmetry group.8 General spectral, physical, and chemical properties of Bx2Hi22-are detailed in a paper by Muetterties et al.9... 

Reactions in which two o bonds terminate at a single atom or made or broken in a concerted chemical reaction are called cheletropic reactions ... 

The difference in reactivity was also found for the paramagnetic surface defects -(=Si-0-)3Si radicals [16]. Since the observed effects are due to the difference in the structure of the nearest environment of the surface silicon atom, it is most pronounced when this atom acts as an active site. This difference should cease with an increase in the number of chemical bonds that separate the active site and surface silicon atom of the solid with which it is linked. They are almost absent for the (=Si-0-)3Si-CFl2- CF[2 radical in which the active site is localized on the terminal carbon atom [16]. For this reason, it is desirable to have a probe in the immediate contact with a lattice silicon atom. The Si-H group fits best these requirements. Such groups can be obtained upon the interaction of the silyl-type radicals with the hydrogen or deuterium molecules (cf. Section 6.3). The IR band due to the stretching vibrations of the Si-Fl bonds obtained upon the hydrogenation of silyl radicals ... 

Two or more vertices within a defined small space indicate the location of an atom in the structure (see Figure 4.9c). Atoms are numbered, and the neighborhood relationship among them is kept. Any atom with only a single neighbor is considered a possible terminal atom. A linear projection of its previous bond up to a distance similar to the length of that bond is made (see Figure 4.9d). If no on-pixels are encountered, the atom is considered a default carbon atom in the structure. Otherwise, the contour determination process is done over the newly found on-pixel. In this way, the detected chemical symbols are submitted to the OCR module. 

The main shortcoming of the cluster approach consists of the scission of the chemical bonds between terminal atoms of a cluster and the rest of a lattice. As a result, so-called dangling bonds occur at the terminal atoms of a cluster, artificial electron surface states appear in the partially occupied band, and the charge distribution is disturbed. A cluster in this case possesses too many surface atoms. Unfortunately, to obtain a better surface/bulk ratio, one should consider such large clusters that the approach becomes useless. 

The situation is different with the other HOMO-LUMO interaction. These orbitals are antisymmetric with respect to the symmetry element, and the two ends of the new linkage are separated by a nodal plane. Therefore, two separate chemical bonds will form, each connecting an ethylene carbon atom with a terminal butadiene carbon atom. From this consideration, it follows that the first symmetric interaction is the dominant one. Also, the symmetric pair (HOMO of ethylene and LUMO of butadiene) are closer in energy and thus give a stronger interaction. 

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