Interplanar distances

Carbon symmetry -letraheJnil isp ) C -C bond length 15.4 nm. trigonal planar sp ) C C bond length 14.2 nm interplanar distance 3J.5 nm... 

As the N knee can have — 1 inner concentric knees, all of them separated by approximately the graphite interplanar distance, is called the graphite layer order . In fact, the number of atoms of the torus is given by 10(24 -l-33 —5n) because 10 atoms are common for adjacent knees at the (5 ,5 )-(5m,5h) connection (see below. Section 2.5). 

Simulated SWCNT ED patterns will be presented below. Tbe most striking difference with tbe MWCNT ED patterns is tbe absence of tbe row of sharp oo.l reflexions. In tbe diffraction pattern of ropes there is still a row of sharp reflexions perpendicular to the rope axis but which now corresponds to the much larger interplanar distance caused by the lattice of the tubes in the rope. The ho.o type reflexions are moreover not only asymmetrically streaked but also considerably broadened as a consequence of the presence of tubes with different Hamada indices (Fig. 3). 

X-ray diffraction analysis of crystalline poly(schiff base)s and their low molecular models shows that the formation of molecular complexes is accompanied by an increase in interplanar distances and, in a number of cases, by complete amor-phization. Molecular complexes of poly(schiff base)s with Br2 decompose with time, because of the bromination of the donor components, forming C—Br bonds. Substitution of hydrogen by bromine in phenyl groups occurs only in cases in which these groups are not included into the main polymeric chain. 

For this range of values of u the structure factor for (154) is much greater than that for (037), if aluminum atoms are at (a) and (b) the observation that the latter plane reflects much more strongly than the former despite its smaller interplanar distance accordingly eliminates this arrangement. 

For arrangements (a) and (b) the structure factor in the first order is 4Ba for planes with hSG even and kSG + lSG even, and 0 for all other planes. These arrangements are definitely eliminated by the experimental data for example, (411)SG is absent, and (521)sg> with smaller interplanar distance, reflects very strongly at the same wave length. Such wide discrepancies cannot be explained as due to the effect of sulfur and oxygen atoms. The barium atoms are, therefore, located as in (c). Because of the presence of other atoms no attempt was made to determine the two parameters involved. 

TABLE 1. The meridional (P-P) diffraction maxima of the MnAU icosatwin fivefold-axis ED photograph (Ref. 3). Values of intensity, / radius, R observed and calculated interplanar distances, and dale and indices. Scale Rd -75.6 mm A, ao —23.36 A. 

Another type of interaction is the association of radical ions with the parent compounds. Recently (118), a theoretical study was reported on the interaction of butadiene ions with butadiene. Assuming a sandwich structure for the complex, the potential curve based on an extended Hiickel calculation for two approaching butadienes (B + B) revealed only repulsion, as expected, while the curves for B + and B + B" interactions exhibit shallow minima (.068 and. 048 eV) at an interplanar distance of about 3.4 A. From CNDO/2 calculations, adopting the parameter set of Wiberg (161), the dimer cation radical, BJ, appears to be. 132 eV more stable than the separate B and B species, whereas the separate B and B species are favored by. 116eV over the dimer anion radical, BJ. This finding is consistent with experimental results formation of the dimer cation radical was proved in a convincing manner (162) while the attempts to detect the dimer anion radical have been unsuccessful. With other hydrocarbons, the reported formation of benzene dimer anion radical (163) represents an exceptional case, while the dimeric cation radical was observed... 

Fig. 18—High resolution TEM plan-view image of TiN/Si3N4 nanocomposite coating with Si content of 10.8 at. % and hardness of 42 GPa. The coating was deposited on NaCI substrate for about 50 nm thick and then was floated off onto a mesh. The crystallites were confirmed to be TIN by the interplanar distance of 0.21 nm, which is the TIN (200) interplanar distance. The gain size of the TiN crystallites is less than 5 nm.

Imagine the variation of interplanar distances expressed in percent. 

The parameters of an elementary crystal cell for initial and finite state are practically identical. For example, interplanar distance C= (6.718 + 0.007)T0"8 cm for NGZ (GAK-1 grade) and NGF dos not change during cycling. 

Adapted from Ref. [177]. Copyright (1996) American Chemical Society) (e) plot of the interplanar distances, dN against the ionic radii of the central atoms [177]. 

Table 8.1 also shows the skew angles . Obviously there seems to be no relationship between the skew angle and the interplanar distance. This may be due to the fact that the calculated interplanar distances are too small, considering the... 

Thus, the two Pc rings of the LnPc2 complexes have a skew angle of about 45° only in the case of the fairly strong it-it contact between the two Pc rings. When the interplanar distance is greater than the usual van der Waals contacts, the skew angle is decreased dramatically. 

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