摘要:

The phase relationships in the gold/selenium system have been examined using X-ray powder diffraction techniques and differential thermal analysis. Only one stable phase, α-AuSe, is formed. A metastable modification of this compound, β-AuSe, is also formed by reaction of the elements. Both forms are monoclinic:α-AuSe: space groupC2,Cm, orC2/m;a = 12.21 ± 2,b = 3.693 ± 4,c = 8.434 ± 6 Å, β = 103.20 ± 3°; cell content, 8(AuSe).β-AuSe: primitive monoclinic (space groupsP21orP21/mare likely);a = 6.27 ± 1,b = 3.668 ± 4,c = 8.35 ± 1 Å, β = 105.95 ± 13°; cell content, 4(AuSe).Both modifications decompose peritectoidally at ca. 400 °C. Gold and selenium form a monotectic at 754 °C at a composition just above 50 at. % selenium; some evidence was obtained for the presence of two liquid phases above the monotectic.Tellurium does not substitute in the AuSe lattice to a detectable extent. However, a ternary phase which includes the composition Au2SeTe is formed. Au2SeTe is primitive orthorhombic witha = 8.924 ± 6,b = 7.56 ± 1,c = 5.741 ± 8 Å. The cell contains 4 formula units. Selenium will substitute for at least 15 at.%of the tellurium atoms in the monoclinic AuTe2calaverite lattice at ca. 400 °C.

ISSN:0008-4042    

DOI:10.1139/v68-433

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

The theory of the generalized mean amplitudes of vibration has been applied to the C3S2molecule, which possesses a linear symmetrical structure. The numerical values of the force constants and the mean square parallel and perpendicular amplitudes at 298°K of all bonded and non-bonded pairs of atoms are calculated from spectroscopic vibrational frequencies by the Cyvin and Morino–Hirota methods, utilizing the symmetry coordinates. The "shrinkage" effect constants are also evaluated by means of the perpendicular mean square amplitudes.

ISSN:0008-4042    

DOI:10.1139/v68-434

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

The general Hamiltonian for the nuclear magnetic resonance (n.m.r.) spectra of oriented 4-spin systems withC2vsymmetry of the type (AA′BB′) is reported. The system can be discussed analytically, if only the direct coupling between the various nuclei is considered. The expressions for transition frequencies and intensities for such a case are given.The proton spectrum of thiophene in the nematic phase ofp,p′-di-n-hexyloxyazoxybenzene has been analyzed. The ratios of the various interproton distances are determined.

ISSN:0008-4042    

DOI:10.1139/v68-435

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

We have reinvestigated in detail the infrared spectra between 4000 and 600 cm−1of the solid products formed by reacting liquid ozone at −190 °C with a stream of hydrogen gas dissociated in an electrodeless discharge. Extreme care was exercised to get "clean" spectra, free from any contaminants. All the spectra thus obtained showed very clearly the characteristic absorption bands of H2O2at 2840 and 1430 cm−1, and the much weaker one at 880 cm−1; with deuterium atoms the former bands were shifted to 2100 and 1080 cm−1respectively. Thus previous contentions that hydrogen peroxide is not one of the primary products of that reaction are disproved. The other infrared bands of H2O2were not conspicuous, due either to their diffuse nature in the vitreous spectra or to extensive overlapping by the strong absorption of H2O, the other major component. Warming the material up to −110 °C caused some devitrification, but no significant change in the spectra. No new bands which could be assigned unambiguously to the hypothetical molecule H2O4were observed.

ISSN:0008-4042    

DOI:10.1139/v68-436

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Rate constants have been measured for the chain-terminating self-reactions of six tertiary peroxy radicals. The rate constants vary from ~ 1 × 103 M−1s−1fort-butylperoxy to ~ 6 × 104 M−1s−1for 1,1-diphenylethylperoxy radicals. It is suggested that the variation in the rate constants may be related to differences in the stability of the alkoxy radical products of tetroxide decomposition.Rate constants for hydrogen atom abstraction from aralkanes by tertiary peroxy radicals do not seem to be significantly affected by the structure of the attacking radical.In solution the triphenylmethylperoxy radical probably exists in equilibrium with the triphenylmethyl radical and oxygen. Chain termination in oxidations involving the triphenylmethylperoxy radical as the chain carrier occurs by the reaction of this radical with a triphenylmethyl radical.

ISSN:0008-4042    

DOI:10.1139/v68-437

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Rate constants have been measured for hydrogen abstraction from four aralkanes and addition to two aralkenes by five secondary and one primary peroxy radical. These rate constants appear to show a slight dependence on the structure of the attacking peroxy radicals which may be due to the inductive effects of the substituents on the radical. The secondary and primary peroxy radicals are generally about 2–4 times more reactive than tertiary peroxy radicals in abstraction and 4–8 times more reactive in addition. The lower reactivity of tertiary peroxy radicals is probably due to steric factors.

ISSN:0008-4042    

DOI:10.1139/v68-438

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Extended Hückel molecular orbital calculations have been performed on localized TiO68−units with the precise geometry of such a unit in solid rutile, anatase, and brookite TiO2and tetragonal BaTiO3. The relative values of one-electron energy levels in these compounds are obtained in terms of a "self-consistent" charge and population calculation. Examination of the resulting energy levels and charge distributions has led to reasonable explanations of previously unexplained data on (1) the visible and near-ultraviolet absorption spectra of these compounds, (2) the low energy X-ray absorption edges of rutile, anatase, and brookite TiO2, and (3) the pressure dependence of the absorption edges of rutile TiO2and tetragonal BaTiO3.

ISSN:0008-4042    

DOI:10.1139/v68-439

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

The carbon-13-proton coupling constantJ13C–Hfor the methyl group is found to correlate linearly with the productEX × γX–C, whereEXis the electronegativity of the substituent X and γX–Cis the X—C bond distance. Unknown values ofJ13C–Hfor the methyl group are predicted from the linear correlation. It is concluded that the "size effect" and the "polarization effect" are important in determiningJ13C–H.

ISSN:0008-4042    

DOI:10.1139/v68-440

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Heats of several reactions involving sodium periodate, NaIO4(c), have been measured in an isothermal jacketed calorimeter. The apparent acid ionization constant of periodic acid was redetermined at an ionic strength of 0.13. From these data the following values for heats of formation at 25.00° have been calculated: NaIO4(c), −105.15 ± 0.30; IO4−(aq), −38.8 ± 0.4; H5IO6(aq), −188.9 ± 1.0; H4IO6−(aq), −186.3 ± 1.0 kcal/mole.

ISSN:0008-4042    

DOI:10.1139/v68-441

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Five mercury complexes were synthesized by condensation of mercuric chloride with different biologically active amines. In the present studyD-amphetamine,L-amphetamine,DL-amphetamine, methyl-amphetamine, ephedrine, and tyramine were used where a stereoisomeric effect was observed during the formation of the mercury complexes. The complex compound synthesized fromDL-amphetamine was found to be a mixture of the mercury complexes ofD-amphetamine andL-amphetamine, and the difference in their solubilities was utilized for their separation. The estimation of the carbon, hydrogen, and nitrogen content, the determination of the amount of chlorine and mercury, and measurements of the infrared absorption spectra at 700–3500 cm−1indicated the ratio of 2:1 for amine to mercury in these coordination compounds. Further characterization of these mercury complexes was done by ultraviolet absorption spectra and conductance measurements.

ISSN:0008-4042    

DOI:10.1139/v68-442

出版商:NRC Research Press    

年代:1968

数据来源: NRC