Geometrically planar

The maximum isosteric differential heat of adsorption interpolated from the heat-coverage plots. c The roughness factor is defined as the ratio of the experimental values of the weight of adsorbate required for monolayer coverage to that calculated for the same coverage of a geometrically planar surface. It can be interpreted as the ratio of the real area to the apparent area of the adsorbent. 

In one of the classical papers on the enumeration of poly hexes, Lunnon [10] found the numbers of all geometrically planar polyhexes with h (number of hexagons) up to 12 see Table 4. In these numbers the helicenic systems are excluded, but all non-helicenic circulenes are included. Hence the numbers pertain to benzenoids plus planar circulenes. The contribution of Balaban and Harary [13] to the Lunnon numbers (cf. footnotes to Table 4) is commented in the next section. The Lunnon numbers have been extended to h = 13 and h = 14 by means of the data from Muller et al. [36]. 

Here a benzenoid system (or shortly benzenoid) [9-13] is defined as a geometrically planar, simply connected polyhex. Consequently, the helicenic and coronoid systems are excluded. The coefficients of the formula C HS, viz. n and s, correspond to the total number of vertices and the number of vertices of degree two, respectively, in the benzenoid. 

The introduction of mono- hexagonal lattices makes it feasible to adapt the notions of geometrically planar/nonplanar and nonhelicenic/helicenic systems to mono—(f-polyhexes in general. 

This chapter deals with certain nonhelicenic (geometrically planar) polyhexes, which may be simply connected (without holes) or multiply connected with a varying number of corona holes. It is recalled that a corona hole by definition should have a size of at least two hexagons. 

A is the real rather than geometric planar electrode surface area touched with the electrolyte solution. For instance, with a xmit of pC.cm", the reciprocal of the overall double-layer differential capacitance with a unit of pF.cm can be expressed as ... 

The behavior of the anticancer agent cis-dichlorodiammineplatinum (II), or cisplatin, is another example of the utility of the method . The adsorptive-stripping/cyclic voltammetric (saturation) data yield a surface coverage of 5.1 x 10- o mol/cm. Each adsorbed molecule thus occupies an area of 33 A 2. This value is in excellent agreement with the area (34 A 2) estimated from the crystal structure of cisplatin. Such agreement suggests the existence of a packed geometrically planar layer of adsorbed cisplatin at the surface. 

The carbon atoms of the double bond have a trigonal planar configuration and free rotation about the C—C bond is prevented by the n bond. The inability to rotate means that geometrical isomers can be produced, with substituents a and b, thus ... 

Recent mathematical work suggests that—especially for nonlinear phenomena—certain geometric properties can be as important as accuracy and (linear) stability. It has long been known that the flows of Hamiltonian systems posess invariants and symmetries which describe the behavior of groups of nearby trajectories. Consider, for example, a two-dimensional Hamiltonian system such as the planar pendulum H = — cos(g)) or the... 

The force exerted on a submerged planar surface of area A is given by F = p A where p is the pressure at the geometrical centroid of the surface. The center of pressure, the point of application of the net force, is always lower than the centroid. For details see, for example. Shames, where may also be found discussion of forces on curved surfaces, buoyancy, and stability of floating bodies. 

Figure 11.19 The geometric requirement for E2 reaction in a substituted cyclohexane. The leaving group and the hydrogen must both be axial for anti peri-planar elimination to occur.

Two or more species with different physical and chemical properties but the same formula are said to be isomers of one another. Complex ions can show many different kinds of isomerism, only one of which we will consider. Geometric isomers are ones that differ only in the spatial orientation of ligands around the central metal atom. Geometric isomerism is found in square planar and octahedral complexes. It cannot occur in tetrahedral complexes where all four positions are equivalent... 

Geometric isomerism A type of isomerism that arises when two species have the same molecular formulas but (Efferent geometric structures, 413 octahedral planar, 415 square planar 414 trans isomer, 414... 

The annulation of 4//-thiopyran and cyclohexane rings in 50a results in the planarity of the heterocycle and a half-chair conformation of the carbocycle (81KGS1342). On the other hand, a boat conformation of the 2//-thiopyran ring was found in the crystal of224b [91JCS(P2)2061], Other geometrical parameters were within the limits of the expected values (Fig. 2). 

Square planar complexes of the type MABCD have three geometric isomers and in several cases all have been synthesized. Therefore, the isomers of [PtClBr(NH3)py] can be synthesized as shown in Figures 3.88-3.90. 

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