摘要:

The quasi-reduced iron–selenium phase diagram has been determined by a combination of differential thermal analysis, visual polythermal, and liquid sampling techniques. Iron and selenium form two compounds: FeSe2with a broad stoichiometry range and FeSe2with a much narrower composition field. The former compound was found to melt congruently at 1070 °C and 53.5 atomic % selenium, while the latter melted incongruently at 585 °C. Two liquid–liquid regions were observed in this system. One occurred above 790 °C from 73.9 atomic % selenium to about 99.92% selenium with a consolute temperature of 1070 °C at approximately 93 atomic % selenium. The other liquid–liquid region extends upwards from 1520 °C and lies between 3 and 39.5 atomic % selenium.

ISSN:0008-4042    

DOI:10.1139/v68-200

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Measurements were made of the velocity of sound in liquid argon in the temperature range 86–146 °K and at pressures up to 65 atm. The velocity versus pressure isotherms are steeper and more curved at the higher temperatures. At any one pressure, the velocity is a smoothly decreasing function of temperature. Analysis of the results using existing density data showed that the specific heat ratio, γ, decreases with pressure and increases with temperature in this range. The coefficient in Rao's relation was found to increase with temperature at constant pressure, while that in the relation due to Carnevale and Litovitz exhibited no definite trend with temperature or pressure.

ISSN:0008-4042    

DOI:10.1139/v68-201

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Water vapor irradiated with X-rays in the presence of nitrous oxide gives mainly nitrogen and oxygen together with small amounts of hydrogen and, possibly, hydrogen peroxide. The yield of nitrogen,G(N2) = 3.0 ± 0.3, is constant over a wide range of conditions andG(O2) = 1.6 ± 0.3 after an induction period. The hydrogen yield is constant at low doses withG(H2) = 0.45 ± 0.1, but reaches a steady state at higher doses. The nitrogen yield is equated with the yield of scavengeable electrons in water vapor, the valueg(e) = 3.0 ± 0.3 being in reasonable agreement with the theoretical value based onW(H2O) = 30 eV. Addition of other electron scavengers to water vapor containing nitrous oxide suppresses the nitrogen yield by competing efficiently for electrons. On the basis of their efficiency in suppressing the nitrogen yield, limiting values for the relative rates of reaction of N2O, SF6, CCl4, and HCl with electrons in water vapor are obtained and comparisons are made with their known electron attachment cross sections in the gas phase.

ISSN:0008-4042    

DOI:10.1139/v68-202

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

The kinetics of oxidation of In–Ag alloys of 5,10, and 15 at. % indium have been studied on a vacuum microbalance. The 15 at. % indium alloy oxidizes externally and the 5 at. % alloy internally. A plot of logarithm of the parabolic oxidation rate,kp, versus reciprocal of the absolute temperature for 10 at. % indium alloy gives two intersecting straight lines corresponding to the energies of activation of 23 and 39.6 kcal/mole for the oxidation below and above 600 °C respectively. These are comparable to the energies of activation of 23 kcal/mole for the internal oxidation of 5 at. % indium alloy and 40 kcal/mole for the external oxidation of 15 at. % indium alloy. The rate–controlling step in the external oxidation of 15 at. % indium alloy is the diffusion of indium through the alloy. Photomicrographs of the cross sections of the oxidized foils of these alloys confirm the conclusions derived from the kinetic data.

ISSN:0008-4042    

DOI:10.1139/v68-203

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

The densities of solid thallium amalgams were measured pycnometrically at −79.0°C with the following results in g/ml: 13.946, 13.851, 13.465, 13.379, 13.219, 13.263, 13.267, 13.264, 13.184, 13.180, 13.177, 13.132, 13.063, 13.055 for the concentrations in weight % thallium of 8.72, 11.15, 19.45, susceptibilities of the amalgams were measured by the Gouy method over the same concentration range at temperatures from −180°C to 150°C. The alloys were diamagnetic and the susceptibilities were compatible with the phase diagram. The densities and the e.m.f. measurements on concentration cells show that the alpha phase at −79°C extends from 21.35 to 30.7 weight % thallium and at 0°C the alpha phase extends to 33.75 weight % thallium.

ISSN:0008-4042    

DOI:10.1139/v68-204

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

This paper reports the first attempt to use Gaussian basis sets in nonempirical self-consistent field (s.c.f.) calculations on sulfur-containing chemical systems. Exponents for Gaussian-type functions (G.t.f.) on S atom are given for the minimal basis set. The optimization procedure is described and the optimized exponents utilized on calculations on S atom, H2S, and the hypothetical dihydrogen sulfoxide (H2SO). Calculations by the minimal basis set of (G.t.f.), using these exponents, gave a value for the HSH angle of H2S that agrees well with the experimentally determined value. Calculations of H2SO support a "multiple bond" picture of the S—O bond.

ISSN:0008-4042    

DOI:10.1139/v68-205

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

The loss of optical activity from phenylbenzylmethylallylammonium iodide in chloroform solution has been found to be entirely due to decomposition; racemization as such does not take place. The products are benzyl iodide and allylmethylaniline. A mechanism involving decomposition via a triple ion is deduced from the reaction kinetics. The activation parameters (ΔH≠and ΔS≠) and a secondary deuterium isotope effect are reported.

ISSN:0008-4042    

DOI:10.1139/v68-206

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

A simple and rapid electrochemical technique for the preparation of uniform and adherent metal deposits on thin metallized plastic films has been developed. It is based on the use of an electrolytic cell, characterized by the separation of the anode and cathode compartments by a fritted glass disc. Furthermore, electrodeposition is achieved from a solution having a volume of only 0.15 ml. The technique and the conditions used to realize the electrodeposition on thin metallized plastic films is described. The cell has been used to electrodeposit many metals, mostly by spontaneous electrodeposition using a magnesium anode and also by application of an external voltage using a platinum anode. In this paper, we describe the experimental conditions and report the results dealing with the electrodeposition of Co, Ni, Ag, Hg, and Zn. Deposits of less than a microgram to several hundred micrograms per square centimeter were obtained with high yields in 10 to 40 min. The use of the technique for the preparation of radioactive sources of Co-60, Ni-63, Ag-110 m, and Hg-203 for absolute rate determinations is reviewed.

ISSN:0008-4042    

DOI:10.1139/v68-207

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

The reaction between nickel and potassium dithio-oxalate has been developed into a simple, quick, and precise method for the spectrophotometric determination of traces of nickel and has been applied to the analysis of this element in our studies on its electrodeposition on thin metallized plastic films. On making absorption measurements of the colored compound formed by the reaction in various bases and acids at different concentrations, it was found that a dilute sulfuric acid solution is a good medium for preparation of samples and making the measurements. Maximum absorption of the compounds occurs at 500 mμ and obeys the Beer–Lambert law over a suitable range. The effect of various ions on the determination of nickel by the method has been measured along with the absorption curves of the compounds formed by the reaction of potassium dithio-oxalate with cobalt and copper. The relative merits of the method are discussed with reference to other methods of analysis of traces of nickel.

ISSN:0008-4042    

DOI:10.1139/v68-208

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Synthetic routes have been developed to salts containing the anions [CF3PF5]−, [(CF3)2PF4]−, [(CF3)3PF3]−, [(CF3)2AsF4]−, and [(CF3)3AsF3]−. These are isolated as stable solids with Cs+, or sometimes Ag+, as the cation. Their19F n.m.r. spectra are discussed, and it is suggested that the bis- and tris-(trifluoromethyl)-substituted fluorophosphates have atransconfiguration.Trimethyltrifluoromethyltin, (CH3)3SnCF3, forms 1:1 complexes with PF5, (CF3)2PF3, and (CF3)3PF2. It is suggested that transfer of a trifluoromethyl group as CF3−has occurred here, leading to the formation of trimethyltin derivatives of the trifluoromethyl-substituted fluorophosphates.

ISSN:0008-4042    

DOI:10.1139/v68-209

出版商:NRC Research Press    

年代:1968

数据来源: NRC