Atoms Lithium

There is evidently a grave problem here. The wavefiinction proposed above for the lithium atom contains all of the particle coordinates, adheres to the boundary conditions (it decays to zero when the particles are removed to infinity) and obeys the restrictions = P23 that govern the behaviour of the... 

As fonnulated above, the FIF equations yield orbitals that do not guarantee that F has proper spin symmetry. To illustrate, consider an open-shell system such as the lithium atom. If Isa, IsP, and 2sa spin orbitals are chosen to appear in F, the Fock operator will be... 

Following fragmentation the alkyl radical rapidly combines with a lithium atom to foim the oiganometalhc compound... 

Some excited configurations of the lithium atom, involving promotion of only the valence electron, are given in Table 7.4, which also lists the states arising from these configurations. Similar states can easily be derived for other alkali metals. 

ButyUithium is available as a 15—20 wt % solution in //-pentane or heptane. Noticeable decomposition occurs after alb reflux in heptane (bp 98.4°C) but not after a 15 min reflux in ben2ene (bp 80.1°C) or hexane (bp 68°C). /-ButyUithium in pentane or heptane is more stable than //-butyUithium in hexane (125). Solutions of /-butyUithium in pentane and heptane are flammable Hquids and are considered pyrophoric. The /-butyl compound is more reactive than either the n- and sec-huty. Di-//-butylether is cleaved by /-butyUithium in 4—5 h at 25°C, compared to the 2 d for j iZ-butyUithium and 32 d for //-butyUithium (126). /-ButyUithium can be assayed by aU of the techniques used for //-butyUithium. /-ButyUithium is a useful reagent in syntheses where the high reactivity of the carbon—lithium bond and smaU si2e of the lithium atom promote the synthesis of stericaUy hindered compounds, eg,... 

The heart of the energy-dispersive spectrometer is a diode made from a silicon crystal with lithium atoms diffiised, or drifted, from one end into the matrix. The lithium atoms are used to compensate the relatively low concentration of grown-in impurity atoms by neutralizing them. In the diffusion process, the central core of the silicon will become intrinsic, but the end away from the lithium will remain p-type and the lithium end will be n-type. The result is a p-i-n diode. (Both lithium-... 

Fig. 22. The capacity of the one volt plateau measured during the second cycle of several series of samples versus the H/C atomic ratio in the samples. The solid line suggests that each lithium atom binds quasi-reversibly to one hydrogen atom.

Fig. 23. When lithium inserts in hydrogen-containing carbon, some lithium atoms bind on the hydrogen-terminated edges of hexagonal carbon fragments. This causes a change from sp to sp bonding [37].

A lithium cluster in the micropores of the carbon sample has a very similar environment as lithium atoms in metallic lithium. Hence, we observe long low-voltage plateaus on both discharge and charge for lithium insertion in the microporous carbon. 

When Li metal is cold-worked it transforms from body-centred cubic to cubic close-packed in which each atom is surrounded by 12 others in twinned cuboctahedral coordination below 78 K the stable crystalline modification is hexagonal dose-packed in which each lithium atom has 12 nearest neighbours in the form of a cuboctahedron. This very high coordination... 

The side-on structure (3) has been established in two dinickel complexes which have very complicated structures involving lithium atoms also in association with the bridging It also... 

A limited number of non-transition-metal derivatives of thiophene will be considered in this subsection. There are no short-range contacts between the lithium atoms originating from the (LiO)6 cores and the sulfur atoms in [Li—O—EMc2 (2-C4H3S)]6 (E = C, Si) (97OM5032), and evidence for Tr-interactions can be found in the X-ray crystal structures of these compounds. Theoretical computations show that a- (S ) Li" " interactions are weak, whereas Tr-Li" contributions are considerable, in accord with the general reasoning on the electronic characteristics of uncomplexed thiophene. 

The vinylic radica1 accepts another electron from a second lithium atom to produce a vinylic anion. . . ... 

Because each lithium atom has one valence electron and each molecular orbital can hold two electrons, it follows that the lower half of the valence band (shown in color in Figure 5) is filled with electrons. The upper half of the band is empty. Electrons near the top of the filled MOs can readily jump to empty MOs only an infinitesimal distance above them. This is what happens when an electrical field is applied to the crystal the movement of electrons through delocalized MOs accounts for the electrical conductivity of lithium metal. 

The structure of LiTa02F2, as reported by Vlasse et al. [218], is similar to a ReC>3 type structure and consists of triple layers of octahedrons linked together through their vertexes. The layers are perpendicular to the c axis, and each layer is shifted, relative to the layer below, by half a cell in the direction (110). Lithium atoms are situated in the centers of the tetragonal pyramids (coordination number = 5). The other lithium atoms are statistically distributed along with tantalum atoms (coordination number = 6) at a ratio of 1 3. The sequence of the metal atoms in alternating layers is (Ta-Li) - Ta - (Ta-Li). Positions of oxygen and fluorine atoms were not determined. The main interatomic distances are (in A) Ta-(0, F) - 1.845-2.114 Li-(0, F) - 2.087-2.048 (O, F)-(0,F) - 2.717-2.844. 

List the number and kind of fundamental particles found in a neutral lithium atom that has a nucleus with a nuclear charge three times that of a hydrogen nucleus and with seven times the mass. 

The beryllium atom has one more electron than does the lithium atom. The fourth electron that enters the beryllium atom can occupy the 2s orbital to give a configuration of Is22s2. The two 2s electrons will be most easily removed, tending... 

There is little new to be said about the bonding capacity of a lithium atom. With just one valence electron, it should form gaseous molecules LiH and LiF. Because of the vacant valence orbitals, these substances will be expected only at extremely high temperatures. These expectations are in accord with the facts, as shown in Table 16-1, which summarizes the formulas and the melting and boiling points of the stable fluorides of the second-row elements. In each case, the formula given in the table is the actual molecular formula of the species found in the gas phase. 

Clearly the fluorine atom holds electrons much more strongly than does the lithium atom. As a result, the electron pair in the lithium fluoride bond is more strongly attracted to the fluorine atom than to the lithium. The energy is lower if the electrons spill toward the fluorine atom. 

Consider a crystal of metallic lithium. In its crystal lattice, each lithium atom finds around itself eight nearest neighbors. Yet this atom has only one valence electron, so it isn t possible for it to form ordinary electron pair bonds to all of these nearby atoms. However, it does have four valence orbitals available so its electron and the valence electrons of its neighbors can approach quite close to its nucleus. Thus each lithium atom has an abundance of valence orbitals but a shortage of bonding electrons. 

Consider the dilemma of the valence electron of a particular lithium atom. It finds eight neigh-... 

Liquid gas boundary curves, 87 Lithium atom, ground state of, 313 Lithium hydride, electronic correlation, 324... 

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