Differences Between Bridges

Figure 3.7 STM images (16 nm x 16 nm) of clean, reduced TiOjfl 1 0) samples showing the difference between bridging oxygen vacancies, surface hydroxyls, and adsorbed water. The sample in (a) was less reduced than the sample in (b). (c) STM height profiles along the [11 0] direction of species indicated in (b). (Reprinted with permission from Ref. [40]. Copyright 2005, Elsevier.)...

A thorough NQR study ( Nb, 35C1, 81Br, 127I) reflects the environmental difference between bridging and terminal halides. The latter resonate at lower frequencies, which was considered to mean that the relative amount of n bonding from halide to metal is much larger for X, than for Xb. 

Yin, L. I., S. Ghose, and I. Adler (1971). Core binding energy difference between bridging and nonbridging oxygen atoms in a silicate chain. Science 173, 633-34. 

Difference between bridging and mean terminal B-H distances. 

Quantum chemical calculations have mostly been limited to small adsorbates such as formic acid (HCOOH) on different ZnO surfaces [449, 450]. Three structures have been suggested for the formate anion adsorbed on metal oxide surfaces bridging, bidentate, and unidentate structures as shown in Fig. 5. The energy difference between bridging structure and unidentate structure in interactions with the surface OH species was calculated to be very small [449]. Thus, theoretical studies of the adsorption of HCOOH on ZnO surface energetically favor a bridging structure, which is also found to be the most stable adsorption mode [449]. However, the results also indicate that the bonding mode of HCOOH on ZnO is sensitive to the... 

The double vertical slash ( ) indicates the salt bridge, the contents of which are normally not indicated. Note that the double vertical slash implies that there is a potential difference between the salt bridge and each half-cell. 

This is a transient discrete electric discharge which takes place between two conductors which are at different potentials, bridging the gap in the form of a single ionization channel (Plate 4). Based on light emission measurements of sparks with symmetrical electrode geometry, the energy is dissipated approximately uniformly along the channel. This is in contrast with asym-... 

Attack ty acetate at C-1 of C-2 would be equally likely and would result in equal amounts of the enantiomeric acetates. The acetate ester would be exo because reaction must occur from the direction opposite the bridging interaction. The nonclassical ion can be formed directly only from the exo-brosylate because it has the proper anti relationship between the C(l)—C(6) bond and the leaving group. The bridged ion can be formed from the endo-brosylate only after an unassisted ionization. This would explain the rate difference between the exo and endo isomers. 

The differences between these structures result first from the intericosahedral B—B bonds linking the chains (e.g., the bridges involving isolated B5 atoms in MgAlB 4 or Mg2B,4 and B5 and B6 atoms in Na,Bo,gBj4), and second from the positions of the metal atoms and their occupancy. Metal atoms occupy interstitial... 

One-electron oxidation of the vinylidene complex transforms it from an Fe=C axially symmetric Fe(ll) carbene to an Fe(lll) complex where the vinylidene carbon bridges between iron and a pyrrole nitrogen. Cobalt and nickel porphyrin carbene complexes adopt this latter structure, with the carbene fragment formally inserted into the metal-nitrogen bond. The difference between the two types of metalloporphyrin carbene, and the conversion of one type to the other by oxidation in the case of iron, has been considered in a theoretical study. The comparison is especially interesting for the iron(ll) and cobalt(lll) carbene complexes Fe(Por)CR2 and Co(Por)(CR2) which both contain metal centers yet adopt... 

The major structural difference between monocyclic and bicyclic compounds should be obvious camphene and camphor exhibit bridged structures. It should be noted, however, that the monocyclic compounds can be further distinguished from each other based on the position of the oxygen atom, located at C-2 in carvone, and at C-3 in pulegone, and in the menthones. Work by others had shown that the... 

The partial oxidation of propylene occurs via a similar mechanism, although the surface structure of the bismuth-molybdenum oxide is much more complicated than in Fig. 9.17. As Fig. 9.18 shows, crystallographically different oxygen atoms play different roles. Bridging O atoms between Bi and Mo are believed to be responsible for C-H activation and H abstraction from the methyl group, after which the propylene adsorbs in the form of an allyl group (H2C=CH-CH2). This is most likely the rate-determining step of the mechanism. Terminal O atoms bound to Mo are considered to be those that insert in the hydrocarbon. Sites located on bismuth activate and dissociate the O2 which fills the vacancies left in the coordination of molybdenum after acrolein desorption. 

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