Refractions bonds

An alternative to improving atomic/ionic refractions was to express molecular refraction through bond increments. A system of bond refractions is definitely superior to the system of atomic refractions, as it allows to account for chemical interactions explicitly. The concept of bond refraction was introduced by Bachinskii [183] who suggested that the molar refraction (as well as volumes, heats of combustion, etc) of organic compounds can be calculated of bond increments. According to Bachinskii, Rc-c =l/4f c + l/4 c. = l/47Jc + etc. This method is not quite con- 

The anisotropy of bond refractions, which can be determined by measuring the Kerr constant, is very useful for studying the nature of the chemical bond [194,195]. It shows that the valence electron cloud is ellipsoidal (with the longest axis in the internuclear direction) and its parameters depend on the polarity and the bond order. The experimental anisotropic bond refractions in molecules A2, AX, AXn, A2X , and M(CsH5)2 (Table SI 1.15) which conform to the formula  

The formation heats of the organic compounds correlate with differences between experimental molar refractions and sums of the corresponding atomic refractions (AR) [198]. Hohm [199] obtained a similar relationship between the atomization energy of inorganic compounds and AR /. However, this correlation can be used only 

---

The values for the D sodium line of the atomic and structural constants and of the bond refractions, as determined by the author, are collected in Tables XI,2A and XI,2B respectively. 

Bindungs-kraft, /. combining force, linkage force, -mittel, n, = Bindemittel, -refraktion. /, bond refraction, -system, n, bond system, linkage system, -vermdgen, n, = Bindever-mdgen. -wirme, /, heat of combination, -weise, /, mode of union. 

The dipole moment of naphthazarin has been deduced from the measurements of the dielectric constants of its solutions in benzene and dioxan, respectively. A heterodyne beat apparatus has been used at 4 4 Mhz, the temperature of the solution was 20°C. The molecular refraction has been computed [8] from standard bond refractions, the experimental determination being impossible because of the strong... 

Boiling-point composition curves, 7-12 Bond refractions, 1036 Boring of corks, 55, 56 Boron trifluoride, 183, 862, 864, 865 Bouveault-Blanc reduction, 247, 249, 250, 812, 832... 

If, instead, we assume that only one bond is perturbed at any one time then it would be the average polarizability that is important. This would lead to the use of the average bond refraction (Rx) rather than the sum of bond refractions in Eq. (1). 

At optical frequencies the molecular polarizability is primarily determined by the outer electrons of the atoms making up the molecule. It has been shown that for a considerable variety of molecules it is possible to make reasonably accurate calculations of the polarizability by assigning an empirically determined polarizability to each type of chemical bond, and then simply adding up these polarizabilities for all the bonds in the molecule (26). In Table 3 we list some of these bond refractions. Alternatively, the refraction can be expressed as a sum of atomic refractions plus increments dependent upon the type of bonding. 

Organic compounds— For a large number of organic compounds it is found that the bond refraction is an additive quantity. As an example of this relationship between the number and type of bonds and the molecular refraction, Table LXXI gives the differences in the values of the molecular... 

Bond Refraction cc Bond Refraction cc Bond Refraction cc... 

Molecule Alolecular refraction cc 1 Bond refraction cc Molecule Alolecular refraction cc Bond refractior cc... 

---