Interpretation of Abnormalities in Atom Polarization in Terms of Electric Moment

Meredith, C. C.; Westland, L.; Wright, George F

doi:10.1021/ja01567a012

Cited by 27 publications

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“…On the other hand, some studies in this laboratory show that the atom polarization of benzoquinone does not exceed a few percent of the electronic polarization (2). i\4oreover, the total polarizations are both solvent and temperature dependent, and the polarizationternperature plots for several solvents intersect a t the value of 37.6 cc, very close to the value obtained ( I ) from the gaseous state (36 cc) when the latter is extrapolated to lower temperature.…”

supporting

confidence: 69%

“…T h e difference cannot be explained in terms of solute purity (19), a t least in one instance, because the material used by Di Carlo and Snlyth (4) and by Meredith et al (2) was prepared in the same laboratory with the same criteria of purity.…”

Section: Tcne-r T C Nq-rmentioning

confidence: 99%

“…The measurements have been made according to earlier descriptions (2) and are recorded as Fig. 2 for T C N E and Fig.…”

Section: Total Polarizationsmentioning

confidence: 99%

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The Electrical Polarization of 1,4-Benzoquinone and Related Substances

Huber¹,

Wright²

1964

Can. J. Chem.

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A determination of the atom polarization of 1,4-benzoquinone from low-frequency infrared absorptions does not confirm the results of Becker and Charney. Therefore the total polarization of this substance must partly be due to orientation of a dipole. Also tetracyanoethylene and tetracyanoquinodi111etl1a11e seem to have appreciable dipole moments although they both have abnormally high distortion polarization.In the gaseous state ( I ) and in solution (2) the total polarization (P, = Po + P, + P A ) of 1,4-benzoquinone has been found to about 37 cc, thus exceeding the electronic polarization (P,) by about 6 cc. Originally (1) this difference was ascribed to abnormally high atom polarizations, an assignment in lieu of orientation polarization ( P o ) which seemingly Ilas been confirmed by observations that microwave absorptions (3, 4) are insufficient to account for a dipole moment and by absence of a negative Kerr effect (5). >lost recently, optical dispersion theory (3, 5 ) has been applied by Beclcer and Charney (6) to the estimation of atoll1 polarization (PA) by calculation froin absorption spectra of 1 ,4-benzoquinone in the 1700 to 50 cin-I region. According to these worlcers the 6 cc difference between total polarization and electronic polarization is accounted largely in terms of this calculation as P A .On the other hand, some studies in this laboratory show that the atom polarization of benzoquinone does not exceed a few percent of the electronic polarization (2). i\4oreover, the total polarizations are both solvent and temperature dependent, and the polarizationternperature plots for several solvents intersect a t the value of 37.6 cc, very close to the value obtained ( I ) from the gaseous state (36 cc) when the latter is extrapolated to lower temperature. Such behavior is presumptive of orientation polarization due to a dipole moment rather than to atom polarization, which ought to be, and has in general been found to be (7), temperature independent.In view of the conflicting opinions in several laboratories we have elected to repeat with benzoquinone our direct deterinination of distortion polarization (P, = P, + P A ) . This analysis is effected by capacitance ineasurements in respect of air on wafers of the solid substance finely ground for random particle orientation and con~pressed to maximum density. Because of the edge effect coinrnon to capacitors of this diameter (about 0.25 in.) a series of different thiclcnesses is ineasured and the apparent dielectric constants, if they are linearly related, are extrapolated to zero thickness. The original value for this extrapolation (2) was 30.1 cc. Our new value derived with more precise equipment is 31.4 cc. This revised value for PD does not vitiate our conclusion about the polarization of benzoquinone. However, the value of PA included in it will depend upon the choice of P, which is subtracted.

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supporting

confidence: 69%

Section: Tcne-r T C Nq-rmentioning

confidence: 99%

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The Electrical Polarization of 1,4-Benzoquinone and Related Substances

Huber¹,

Wright²

1964

Can. J. Chem.

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“…The solvents used for dielectric-constant studies were purified and maintained a s was described previously (1). Dicyanobiphenyl, prepared according to Ferris and Turner (13), was obtained in 70y0 yield, m.p.…”

Section: Purification O F Materialsmentioning

confidence: 99%

“…The procedures and equipment described previously (1,18) For personal use only. c o n s t a n t (2.2410) a n d t h e specific v o l u m e (1.1675) f o u n d for t h e p u r e solveilt i m m e d i a t e l y after reassembly of the cell.…”

Section: Dielectric-constant Measurementsmentioning

confidence: 99%

Some Anomalous Electrical Polarizations

Podleschka¹,

Westland²,

Wright³

1958

Can. J. Chem.

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Dielectric-constant determinations of a series of solids previously reportecl to have high atom polarizations have not confirmed earlier opinions. Moreover, when it has been practicable to determine the change in polarization with respect to temperature, the relationship is not invariant. This variation may be, and in some instances s h o~~l d be, interpreted as evidence for orier~tatiori polarization. However, all such assignments cannot be certain until the change i l l solid dielectric constant with respect to temperatnre has been studied. INTRODUCTIONThis report is a colltilluatio~l of recent (I) work showing that many electrical polarizations formerly attributed entirely to distortion polarization seem instead to have a component of orientation polarization in an applied field of about 1 electrostatic volt a t 500 kc. These reassignments were based on dielectric constants of thin pellets pressed to maximum density from ralldonlly oriented powders and were confirmed by determinatio~ls of the dielectric constants in benzene solutions a t several temperatures. The present results, shown in Table I , also have previously been assigned abnormally high atom polarizations in lieu of orientation polarizations. These assignments seem to have been made in deference to current organic chemical theory or by analogy with another substance of the same class. I t is evident from the data of Table I that the earlier opinions require revision. Each item will be discussed in order of appearance in the table. p,p'-Dicya)zobiphenyIIn our earlier publication we doubted that the total polarization of 4,4'-dinitrobiphenyl in benzene could be due to electronic plus atomic polarization alone, because our distortion-polarization determinatio~~ was only 0.8 cc. inore than a reasonable value for electronic polarization. i\loreover, our total polarization in benzene was about 10 cc.' J f a n~~, s c r i p t receirlcd iVoue?ttber 20, 1057.

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Metal β‐Ketoenolate Complexes

Fackler¹

1966

Progress in Inorganic Chemistry

248

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Interpretation of Abnormalities in Atom Polarization in Terms of Electric Moment

Cited by 27 publications

References 0 publications

The Electrical Polarization of 1,4-Benzoquinone and Related Substances

The Electrical Polarization of 1,4-Benzoquinone and Related Substances

Some Anomalous Electrical Polarizations

Metal β‐Ketoenolate Complexes

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