摘要:

The primary processes in the mercury-photosensitized decomposition of propane and three deuterated propanes have been studied at low pressures. The primary radicals were trapped by methyl radicals, from thein situdecomposition of dimethyl mercury, and the products measured by gas chromatography. The trapping technique was checked by using 1-chloropropane, 2-chloropropane, and their mixtures. The butane yields were representative of the primary radical yields.The ratio ofi-butane ton-butane from the propane reaction was found to be dependent on light intensity, which fact, not having been recognized before, vitiates earlier results. The ratio varied between 0.3 (at high intensity) and 8.5 (at low intensity). Thei-propyl ton-propyl split in the primary step of propane is 9.1 to 1.0, as found earlier by Holroyd and Klein.

ISSN:0008-4042    

DOI:10.1139/v67-374

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Cadmium pyrovanadate crystallizes in theC2/mspace group with lattice parametersa = 7.088(5) Å,b = 9.091(5) Å,c = 4.963(5) Å,β = 103°21(5)′, andz = 2. This crystal is an isostructure of the mineral thortveitite and thus the anion consists of a pair of centrosymmetrically related corner-sharing VO4tetrahedra while the cation resides within a distorted octahedron of oxygen atoms. The anion has a linear V—O—V group, but, as with the isostructural pyrophosphates, the central oxygen atom shows an anomalously high thermal activity. The V—O bond distances are 1.76 Å for the inner bond and 1.70 Å for the terminal bond. The bond angles about the anion and cation are similar to those found for the other analogues of thortveitite.

ISSN:0008-4042    

DOI:10.1139/v67-375

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

β-Zn3(PO4)2crystallizes in the monoclinic space groupP21/cwith lattice parameters,a = 9.393(3) Å,b = 9.170(6) Å,c = 8.686(3) Å,β = 125.73(10)°, andZ = 4. The three independent cations are strongly ligated to 4, 5, and 5 oxygen atoms, with average Zn—O bond distances of 1.98 ± 0.09 Å, 2.10 ± 0.10 Å, and 2.08 ± 0.13 Å respectively. In addition there are two longer Zn—O distances of 2.51 Å and 2.55 Å in this structure. The PO4groups exist as independent, nearly regular tetrahedra, with each oxygen atom ligated to two cations. Unlike the structures found for the α and γ phases of Zn3(PO4)2, which contain ribbons and sheets respectively as the basic cation coordination motif, the structure of β-Zn3(PO4)2contains interconnected sheets.

ISSN:0008-4042    

DOI:10.1139/v67-376

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The kinetics of formation of sodium hexachlorozirconate from sodium chloride single crystals and zirconium tetrachloride vapor at about 600 Torr have been investigated by the weight-gain method. Analysis of the results showed the formation reaction to be diffusion controlled, with zirconium tetrachloride being the most probable diffusing species. The apparent energy of activation has been determined for this reaction from the variation of the rate constant with temperature, and it was found to be 12.3 ± 3 kcal/mole. The Arrhenius rate equation for the formation of Na2ZrCl6from NaCl and ZrCl4at 600 Torr pressure, in the temperature range 400 to 500 °C, iswhere the units of the parabolic rate constant,K, are (g(Na2ZrCl6))2cm−4h−1.

ISSN:0008-4042    

DOI:10.1139/v67-377

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Zinc, cupric, and ferric fluorosulfates have been prepared. The Raman and infrared spectra of potassium fluorosulfate and the infrared spectra of calcium, zinc, cupric, and ferric fluorosulfates have been measured from 33 to 4 000 cm−1. Evidence for covalent bonding in the cupric and ferric fluorosulfates has been found. The magnetic properties of cupric and ferric fluorosulfates have been studied, and ferric fluorosulfate has been found to be magnetically concentrated. The thermal decomposition of zinc, cupric, and ferric fluorosulfates is reported.

ISSN:0008-4042    

DOI:10.1139/v67-378

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Rates of the possible cross-disproportionation reactions of these radicals relative to their rates of cross-combination, have been measured and are compared with auto-disproportionation-to-combination ratios which were also determined for these radicals. Selected asymmetric azo alkanes RNNR′ and mixtures of symmetric azo alkanes RNNR were used as sources of the desired free radicals. Photolysis under relatively high intensity conditions (ca. 1018quanta/cm2s) at room temperature generated the radicals in sufficiently high concentration that competing reactions of abstraction and condensation were negligible. Both the alkene and alkane products of disproportionation reactions were measured to ensure the completeness of the mechanism invoked and to increase the accuracy of the results. Δ(Me, Et) = 0.036 ± 0.003, Δ(Me, Prn) = 0.058 ± 0.004, Δ(Me, Prs) = 0.163 ± 0.005, Δ(Et, Prn) = 0.065 ± 0.005, Δ(Et, Prs) = 0.18 ± 0.008, Δ(Prn, Et) = 0.057 ± 0.005, Δ(Prs, Et) = 0.12 ± 0.01, and Δ(Prn, Prs) = 0.41 ± 0.02 were deduced from the data, where Δ(A, B) refers to the ratio of disproportionation producing the alkane product derived from A to the combination of A with B.

ISSN:0008-4042    

DOI:10.1139/v67-379

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Co(II)– and Ni(II)–2,2′-biquinoline (Biq) complexes of the type MBiqCl2and MBiq(NO3)2have been isolated. Electronic absorption spectra in the visible and near infrared, as well as magnetic measurements, show that CoBiqCl2is essentially tetrahedral, whereas NiBiqCl2and the MBiq(NO3)2complexes are pseudo-octahedral. In acetone solution Co(II) forms a bis-Biq complex that is probably five coordinate, whereas the Ni(II) analogue is probably an octahedral species with acisconfiguration. Elementary ligand field theory has been used to interpret the absorption spectra, and certain electronic transition assignments have been made that may be of general interest.

ISSN:0008-4042    

DOI:10.1139/v67-380

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Simulated infrared absorption bands of condensed phase systems have been fitted with simple analytical functions by least-squares procedures. The bands were of Cauchy (Lorentz) contour and were modified to conform with the finite spectral slit distortion of the spectrophotometer. Cauchy, Cauchy–Gauss product, and Cauchy–Gauss sum functions were used in the fitting procedures using transmittance ordinates. The fits achieved were compared and the dependence of the optimized indices on the band distortion and data range were analyzed. Some preference for the Cauchy–Gauss sum function is indicated.

ISSN:0008-4042    

DOI:10.1139/v67-381

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Diffusion coefficients and intrinsic viscosities of the cellodextrins, cellobiose to cellohexaose, were measured in aqueous solution at 25 °C. Axial ratios of the oligomers were computed by the Stokes–Einstein diffusion equation modified for non-spherical particles by Perrin's theory, and by the Einstein–Simha viscosity equation. The hydrodynamically calculated axial ratios were equal to the corresponding axial ratios determined from fully extended Stuart–Briegleb models after allowances were made for hydration. Thus the cellodextrins appear to be rodlike and give no indication of pronounced flexibility or folding in aqueous solution at 25 °C.

ISSN:0008-4042    

DOI:10.1139/v67-382

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Intrinsic viscosities of the cellodextrins, cellobiose to cellohexaose, were measured in aqueous solution at temperatures from 25 to 70 °C. Axial ratios were determined using the Einstein–Simha viscosity relation and the computational methods developed previously. The results showed that the oligomers are fully extended over this temperature range and that the negative temperature coefficients of the intrinsic viscosities are caused by the dehydration of the molecules with increasing temperature.

ISSN:0008-4042    

DOI:10.1139/v67-383

出版商:NRC Research Press    

年代:1967

数据来源: NRC