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An electron energy loss spectroscopic study has shown the presence of superoxo species besides two peroxo species on the surface of polycrystalline silver, an observation of much significance to catalysis.
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The molecular structure of trichloroacetonitrile has been studied by electron diffraction by the visual interpretation of sectored photographs. These parameters were obtained: C-N = 1.165 ± 0.025, C-C = 1.465 ± 0.025, C-Cl = 1.765 ± 0.01 A., and < CCCl = 109.5 ± 1°.
Infrared and Raman spectroscopic studies of CsHSO4 suggest the occurrence of the following phase transitions:IV ⇆ 340 K III ⇆ 380 K II ⇆ 417 K I. While the ordered phase, IV, has a monoclinic structure, the high-temperature superionic phase, I, has a tetragonal structure involving the free rotation of HSO- 4. Phase II is close to being orthorhombic with a small monoclinic distortion. The transition to the superionic phase, I, is accompanied by the appearance of broad, structureless bands in the infrared and Raman spectra, as well as changes in the O-H stretching region due to decrease in hydrogen bonding. Accompanying the III-II transition, we observe the disappearance of the O ··· O stretching and δ(S-OH) bands and a decrease in the HSO- 4 libration frequency. Across the phase transitions, the separation between the v(S-O) and v(S-OH) bands shows stepwise changes. The high-temperature superionic phase essentially has sulfate-like species with a relatively short S-O bond, in contrast to the low-temperature phase, which has long and short S-O distances. Substitution of Cs by Li in CsHSO4 has an effect similar to that of increasing the temperature. The vibrational spectrum of Cs0.7Li0.3HSO4 corresponds to a state of disorder between those of phases II and I.
No abstract is provided for this article.
No abstract is provided for this article.
Cubic cuprates (a ∼ 18.6 Å) with a BaCuO2-type structure were obtained in the Ba-Pb-Cu-O and Ba-Bi-Cu-O systems by the reaction of the component oxides at a high temperature (1370-1420 K), followed by quenching. By annealing these phases in oxygen at 1070-1120 K, perovskite-like phase (a ∼ 4.3 Å) of the formulae BaPb1-x Cu x O3-y and BaBi1-x Cu x O3-y (0 < x ≤ 0.5) were obtained. A perovskite of nominal composition BaPb0.25Tl0.25 Cu0.5O3-y , prepared by a similar procedure, was found to be superconducting with a T c of ∼ 70 K.
An elegant method to synthesize porous silver monoliths using a simple surfactant cum reductant, Triton X-114, as the sacrificial template is described. The gel forming property of the surfactant with silver nitrate is utilized to make the porous framework. The monoliths obtained with a mixture of Triton X-114 and dextran have also been examined. A significant improvement in the pore structure was observed when Triton X-114 was used along with Ludox silica sol, followed by calcination and HF treatment. The presence of interparticle pores in the 20–25nm range on the macroporous silver framework suggests the role of silica spheres in the nanopore formation.
In this communication, alternative structures of YBa 2 Cu 3 O 7−δ (δ=0.0−0.5) are discussed making use of the results from thermogravimetric analysis and electron microscopy. Possible orbital orderings in YBa 2 Cu 3 O 7 corresponding to the different structures are also discussed. Magnetic susceptibility data of the non-superconducting δ=0.5 phase are briefly examined.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystallographic Data 196. Titanium Dioxide (Brookite), TiO2S. R. Yoganarasimhan and C. N. R. RaoCite this: Anal. Chem. 1961, 33, 1, 155Publication Date (Print):January 1, 1961Publication History Published online1 May 2002Published inissue 1 January 1961https://pubs.acs.org/doi/10.1021/ac60169a056https://doi.org/10.1021/ac60169a056research-articleACS PublicationsRequest reuse permissionsArticle Views211Altmetric-Citations9LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
Use of tributylphosphate, an organophosphate, as the phosphorus source in place of phosphoric acid, has enabled the synthesis of several new open-framework zinc(II) and cobalt(II) phosphates, under solvothermal conditions.
Dissociation energies of 1:1 complexes of hydrogen, lithium and sodium halides with water, methanol and ammonia vary in the order LiX > NaX > HX, the dissociation energy in the case of lithium bonds being of the order of 200 kJ mol−1 or more. The dissociation energy of sodium bonds lies in the range 80–120 kJ mol−1. The magnitude of charge transfer, Δq, between the donor and acceptor molecules is also highest in the case of lithium bonds. The dissociation energies and Δq have been related with various properties of the complexes.
