Configurational equivalence

Covalent bonding in F2 gives each fluonne eight electrons in its valence shell and a stable electron configuration equivalent to that of the noble gas neon... 

Another innovation related to power SiC DMOSFET was a transistor structure, where the p-type base region was not electrically shorted to the source but could be biased independently as a p-type gate. Such a configuration, equivalent to plugging a VJFET fed from an accumulation channel in parallel with a BJT, resulted in a dramatic reduction of specific on-resistance. A schematic cross section of this device, denoted as static induction injected accumulated FET (SIAFET) and reported by Sugawara et al. in 2000 [40], is shown in Eigure 5.12. 

It should be explicitly noted that the existence of one symmetry plane gives rise to, requires, or, as usually stated, generates one symmetry operation. We may also note here, for future use, that the effect of applying the same reflection operation twice is to bring all atoms back to their original positions. Thus, while the operation or produces a configuration equivalent to the original,... 

FIG. 13-77 (a) Configuration equivalent to thermally coupled system, but without vapor intercoimecting streams, (b) Heat-integrated thermally coupled system. 

In a chiral solution that is not a racemic mixture, however, the chiral molecules present in greater numbers are configurationally equivalent to each other, and therefore each possesses identical electron clouds to its molecular twins. As such, each interaction between light and one of these majority molecule s electron clouds will result in rotations of identical magnitude and direction. When these billions of billions of interactions are summed together into one cohesive number, they do not cancel one another as racemic and achiral solutions tend to do - rather, the chiral solution as a whole is observed to rotate polarized light in one particular direction due to its molecular properties. 

Configurations equivalent to s, under figure index symmetry constitute the right coset of the isomorphic image of P with respect to s,... 

Only the electrons in an atom s valence shell are involved in covalent bonding. Fluorine, for example, has nine electrons, but only seven are in its valence shell. Pairing a valence electron of one fluorine atom with one of a second fluorine gives a fluorine molecule (F2) in which each fluorine has eight valence electrons and an electron configuration equivalent to that of the noble gas neon. Shared electrons count toward satisfying the octet of both atoms. 

An example of a shift of H between alternative C atoms is provided by Equation 13.253, and in the special case where the alternative forms are configurationally equivalent, the molecule is flux-ional (13.254) (Chapter 3.2). 

Rotation-reflection operations in (a) SiCfi, drawn looking down the S4 axis note that in this example neither the rotation hy 2tt/4 hy itself nor the reflection in a plane perpendicular to this axis generate a configuration equivalent to the initial one, hut the combined operation does (b) Sn(T -C5Ph5)2, showing an almost perfect Sio operation, looking down the axis. Reprinted with permission from [2]. Copyright 1984 American Chemical Society. 

The Diels-Alder cycloaddition of highly substituted cyclopentadienones to 1-nitro-ald-l-enitol derivatives give rise to thermally unstable nitro bicyclo[2.2.1]-hept-2-en-7-one cycloadducts which are readily converted to 1-C-aryl-l-deoxy-pentitols. Thus 3 can be converted into 4. A similar reaction is observed for the g/wco-configured equivalent of 3. ... 

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