Orbital configuration, with

SC Spin-Coupled. A VB computational method that uses OEOs and calculates the wave function of an electronic system using a single orbital configuration with all the possible spin-pairing schemes. The method is similar in spirit to GVB. 

For Lij and BCj, the molecular orbital configurations of Table 4-1 generate the valence-bond structures Li—Li and Be Be , with one bond and no bonds, respectively. In contrast to what is the case for Li2, the diatomic molecule Be2 does not exist as a stable species. For N2 and F2, we obtain the Lewis octet structures (namely = and F—F ) from the molecular orbital configurations, (with. These structures have triple and single bonds, respectively. The peroxide anion Ol is isoelectronic with F2, and its valence-bond structure... 

It seems now that both Samuel and Wheland held the widespread opinion that valence-bond structures for diamagnetic molecules must only have electron-pair bonds. Samuel and Wheland had attempted to transform the molecular orbital configurations for N2 and NO so that they would obtain electron-pair bonds for N2O. But neither worker used the correct procedure to obtain valence-bond stractures from diatomic molecular orbital configurations with one or more singly-occupied anti-bonding molecular orbitals. The technique that should be used was developed by Linnett in 1956 , and then by Green and Liimett in 1960 °, and it has formed the primary Pauling 3-electron bond basis for the increased-valence theory we use in this book. When this theory is applied to the excited Nj and NO... 

We note that the overlap depends on the type of orbital configuration j (as specified by the number of unpaired electrons) and also on the particular determinant m and CSF n that are chosen within this configuration type. However, the overlaps are the same for all orbital configurations with the same number of unpaired electrons see (2.6.10). 

The electron configuration is the orbital description of the locations of the electrons in an unexcited atom. Using principles of physics, chemists can predict how atoms will react based upon the electron configuration. They can predict properties such as stability, boiling point, and conductivity. Typically, only the outermost electron shells matter in chemistry, so we truncate the inner electron shell notation by replacing the long-hand orbital description with the symbol for a noble gas in brackets. This method of notation vastly simplifies the description for large molecules. 

Tomita, K., and Fukui, K., Progr. Theoret. Phys. Kyoto) 10, 362, "On the electronic structure of LiH. Atomic orbital approach with configuration interaction."... 

Tsuda and Oikawa (1989) investigated the photolysis of the 1,2-isomer of 10.89 (1,2-benzoquinone diazide) by means of MINDO/3 molecular orbital calculations with configurational interaction. These authors came to the conclusion that no ketocarbene of the type of 10.90 is formed, but that the rearrangement into the cyclopentadienyl ketene 10.94 is a concerted reaction in which the elimination of nitrogen and the rearrangement take place simultaneously. In the opinion of the present author the theoretical result for 1,2-quinone diazide is not necessarily in contradiction to the experimental investigations of Sander, Yankelevich et al., and Nakamura et al., as the reagents used were not exactly the same. 

A note on good practice Note that a configuration with a single electron in an orbital is written with a superscript 1, as in t2not tlgef. 

C08-0129. No elements have ground-state configurations with electrons in g (/=4) orbitals, but excited states... 

Triatomic species can be linear, like CO2, or bent, like O3. The principles of orbital overlap do not depend on the identity of the atoms involved, so all second-row triatomic species with 16 valence electrons have the same bonding scheme as CO2 and are linear. For example, dinitrogen oxide (N2 O) has 16 valence electrons, so it has an orbital configuration identical to that of CO2. Each molecule is linear with an inner atom whose steric number is 2. As in CO2, the bonding framework of N2 O can be represented with sp hybrid orbitals. Both molecules have two perpendicular sets of three tt molecular orbitals. The resonance structures of N2 O, described... 

In a crystal-field picture, the electronic structure of iron in the five-coordinate compounds is usually best represented by a (d yf idyz, 4cz) ( zO configuration [66, 70], as convincingly borne out by spin-unrestricted DFT calculations on the Jager compound 20 [68]. The intermediate spin configuration with an empty d 2 yi orbital in the CF model, however, has a vanishing valence contribution to the... 

Both are essentially planar, i.e. sp2 hybridised, at the radical carbon atom for only in this configuration is maximum p/n orbital overlap— with consequent stabilisation—possible. The stability of a radical increases as the extent of potential delocalisation increases thus Ph2CH- is more stable than PhCH2-, and Ph3C- (cf. p. 300) is a pretty stable radical. 

In contrast, the very similar compound methyl (pyridine) cobaloxime captured electrons into the Co-Me o orbital, probably with concomitant loss of pyridine (82). Well-defined doublet splittings were obtained when the 13CH3 derivative was used, and the spectrum had the form expected for a dzz configuration (Figure 6). The contrast in reactivity between these similar compounds is remarkable. 

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