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Showing papers in "Journal of the American Chemical Society in 1960"



Journal ArticleDOI
TL;DR: In this paper, the decomposition pressure of magnesium hydride was measured under conditions such that the precision and accuracy of the temperature and pressure measurements could be estimated and the composition of the solid phases determined.
Abstract: The decomposition pressure of magnesium hydride was measured under conditions such that the precision and accuracy of the temperature and pressure measurements could be estimated and the composition of the solid phases determined. The diffusion of hydrogen through the walls of the apparatus and the solubility of hydrogen in the walls was considered. The apparatus and the method of making the measurements are described. The decomposition pressures were converted to fugacities hy use of the BeattieBridgeman equation of state for hydrogen and fitted to straight lines to give R ln f/sub H/sub 2/ = (-17,785 plus or minus 76)/T + 32.28 plus or minus 0.45 acd R ln f/sub D/sub 2/ = (- 17,480 plus or minus 110)/T + 32.48 plus or minus 0.17. Magnesium hydride, MgH/sub 2/, was found to be a stoichiometric compound within the limits of error of the measurements. The solubility of hydrogen in magnesium was found to increase from 2 atom% at 440 deg to 10 atom% at 560 deg . From these measurements thermodynamic functions for the formation of magnesium hydride and magnesium deuteride were estimated. (auth)

489 citations






Journal ArticleDOI
TL;DR: The photolysis of suitably constituted organic nitrites provokes an intramolecular exchange of the NO of the nitrite residue with a hydrogen atom attached to a carbon atom in the y-position.
Abstract: The photolysis of suitably constituted organic nitrites provokes an intramolecular exchange of the NO of the nitrite residue with a hydrogen atom attached to a carbon atom in the y-position. The C-nitroso compounds thus formed can be isolated as the corresponding nitrosodimers or, after isomerization , as the oximes. Adequate structural proof has been provided for several examples of the reaction. The mechanism of the process has been discussed and an interpretation of all the relevant facts presented.

346 citations



Journal ArticleDOI
TL;DR: In this paper, an analysis of the electron magnetic resonance of single crystals of malonic acid that were subjected to x-ray damage indicates that the principal long-lived paramagnetic species produced by the xray darnage is a pi-electron radical, that the unpaired electron is concentrated almost entirely on the alpha -carbon and that the spin density on the sigma -proton is negative.
Abstract: An analysis of the electron magnetic resonance of single crystals of malonic acid that were subjected to x-ray damage indicates that: (a) the principal long-lived paramagnetic species produced by the x-ray darnage is gen atoms of this radical are oriented in the crystalline lattice in the same way as these atoms are arranged in the parent undamaged malonic acid molecule. (c) The z,x,y components of the diagonal (electron-spin) - (nuclear-spin) coupling dyadic for the proton attached to the alpha -carbon atom are found to be of the same relative sign and of magnitudes 29. 61, and 91 Mc, respectively. In this orthogonal axis system, z is the CH bond direction and x is perpendicular to the plane of the three carbon atoms. These results are in excellent agreement with theoretical values of the distributed dipole and contact hyperfine interactions and show that this molecule is a pi -electron radical, that the unpaired electron is concentrated almost entirely on the alpha -carbon and that the spin density on the in-plane sigma -proton is negative. The observed g-factors for this radical are g/sub x/ = 2.0026, g/sub y/ = 2.0035, and g/sub z/ = 2.0033 and are in good qualitative agreement withmore » previous theoretical estimates of these quantities. (auth)« less

340 citations
















Journal ArticleDOI
TL;DR: In this article, the flash technique used earlier to study the metastable states of chlorophyll was applied to tetraphenylporphine, zinc tetramerphine and bacteriochlorophyll in toluene and pyridine solution.
Abstract: The flash technique used earlier to study the metastable states of chlorophyll was applied to tetraphenylporphine, - zinc tetraphenylporphine, and bacteriochlorophyll in toluene and pyridine solution. The spectra all show a main band just below the Soret peak, as well as other regularities. The decay law is again --dC*/dt = k1C* + k2(C*)2 + The respective rate constants for all the compounds are almost the same, except for a much faster first-order decay in bacteriochlorophyll. Finally, little or no flash-bleaching is observed with the Cu2+, Co2+, and Ni2+ complexes of tetraphenylporphine.