The theory presented in an earlier paper
is here developed as a method for the evaluation of' true dipole moments from
data obtained from solutions in polar solvents. As illustrations, the new
method is applied to values relating to solutions of several substances in
chloroform, chlorobenzene, and nitrobenzene. The results, considering the
nature of the problem, are satisfactory. The accuracy is greatest when the
solute is highly polar and the dielectric constant of the solvent small.
Aqueous solutions of pyridine and of two amino acids are also considered. In
the latter cases especially, the predicted dipole moments agree most favourably
with anticipated values obtained for the zwitterions by multiplying the
electronic charge by the expected charge separation.
Bond Orders in, Da'benzo [cd,lm]perylene.* By E. THEAL STEWART. [Reprint Order No. 4906.1CALCULATION of the bond orders and the free valences in dibenzo [cd,h]perylene by the method of molecular orbitals (Coulson, " Valence," Oxford University Press, 1952, Ch. 9) gives the results shown in the molecular diagram, bond order being shown on the left and free valences on the right.
Some earlier theories in which attempts
have been made to allow for the influence of molecular shape on the static
dielectric constant of a liquid are shown to be inaccurate. A general equation
is derived for the dielectric constant of a liquid, and this is then applied to
a molecular model consisting, in the first instance, of an ellipsoid uniformly
polarized in a principal direction, and secondly, to an optically anisotropic
ellipsoid ; in both cases the surroundings are assumed to form a continuum. The
results of this more general approach applied to several substances are more
satisfactory than those obtained by the original Onsager theory. The theory is
also applied to mixtures, and in the special case of a dilute solution in a
non-polar solvent, the equation of Ross and Sack is obtained when the ellipsoid
is isotropic. A correlation has been noted in the discrepancies found when the
dipole moment of a substance is calculated by means of observations on the pure
liquid and on dilute solutions in a non-polar solvent, using the equations
derived in the present paper.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.