No abstract is provided for this article.
No abstract is provided for this article.
Based on XPS and UVPS studies, it is shown that oxygen is preferentially adsorbed molecularly in the singlet state on Cu and Ag surfaces containing presorbed chlorine. Adsorption of chlorine on Cu and Ag surfaces containing presorbed atomic oxygen causes a disappearance of the oxygen. Extended Hückel calculations predict the observed behaviour.
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Ferromagnetism is a well-known phenomenon wherein solids exhibit spontaneous magnetization even in the absence of an external magnetic field. An important characteristic of ferromagnetic materials is the hysteresis loop found in the relationship between magnetization and magnetic field. The electrical analogue of ferromagnetic materials are ferroelectric materials1 which show a hysteresis loop in the relationship between polarization and electric field, and exhibit spontaneous polarization in the absence of an external electric field. These materials therefore possess permanent dipole moments, the dipoles arising from the absence of a centre of symmetry. A wide variety of compounds are known to exhibit ferroelectricity.7 These include oxides of perovskite structure (e.g. BaTi03), hydrogen bonded solids (e.g. Rochelle salt, KH2P04), tungsten bronze type structures, pyrochlores, simple salts (e.g. (NH4)2S04, NaN02, KN03), alums, organic compounds (e.g. thiourea, glycine sulphate) and binary compounds as simple as HCl, FeS, GeTe, and V3Si.
Two layered vanadyl selenites with the compositions, [DABCOH2]0.5[(VIVO)(HSeO3)(SeO3)].H2O,I, and [enH2][(VivO)2-(VVO)O2(SeO3)3]-.1.25H2O, II, have been prepared by the reaction of NaVO3 with SeO2 or H2SeO4 under hydrothermal conditions in the presence of organic amines. Crystal data: I, orthorhombic, space group Pbcn (No. 60), a = 6.3152(3) A, b = 18.1918(8) A, c = 17.7172(8) A, V = 2035.4(2) A3, Z = 8, R1 (all data) = 0.0368; II, triclinic, space group P1 (No.2), a = 6.3406(2) A, b = 10.2085(3) A, c = 13.2551(10) A, alpha = 101.238(2) degrees, beta = 96.503(2) degrees, gamma = 104.332(2) degrees, V = 803.47(4) A3, Z = 2, R1 (all data) = 0.0814. While I contains the ladder motif, commonly found in open-framework metal phosphates, II is formed by a secondary building unit composed of a V4O18 cluster along with SeO3 and VO5 groups. The study demonstrates that the selenite unit can be fruitfully exploited to design interesting open-framework structures.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInternational cooperation in educational technologyC. N. R. Rao Cite this: J. Chem. Educ. 1976, 53, 5, 295Publication Date (Print):May 1, 1976Publication History Received3 August 2009Published online1 May 1976Published inissue 1 May 1976https://doi.org/10.1021/ed053p295.2RIGHTS & PERMISSIONSArticle Views33Altmetric-Citations2LEARN 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 InReddit PDF (1022 KB) Get e-Alerts Get e-Alerts
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectron spectroscopic studies of oxygen and carbon dioxide adsorbed on metal surfacesP. Vishnu Kamath and C. N. R. RaoCite this: J. Phys. Chem. 1984, 88, 3, 464–469Publication Date (Print):February 1, 1984Publication History Published online1 May 2002Published inissue 1 February 1984https://pubs.acs.org/doi/10.1021/j150647a028https://doi.org/10.1021/j150647a028research-articleACS PublicationsRequest reuse permissionsArticle Views192Altmetric-Citations48LEARN 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 options Get e-Alerts
No abstract is provided for this article.
No abstract is provided for this article.
The study of reactions involving solids is an important aspect of solid state chemistry from the point of view of understanding the influence of structure and imperfections on the chemical reactivity of solids. It is important to identify the factors governing solid state reactivity in order to be able to synthesize new solid materials with desired structure and properties. Solid state reactions differ from those in homogeneous fluid media in a fundamental respect; whereas reactions in the liquid or the gaseous state depend mainly on the intrinsic reactivity and concentration of the chemical species involved, solid state reactions depend to a large extent on the arrangement of the chemical constituents in crystals. The fact that the constituents are fixed in specific positions in crystals introduces a new dimension in the reactivity of solids, not present in other states of matter. In other words, chemical reactivity is determined more often by the crystal structure and defect structure of solids rather than by the intrinsic chemical reactivity of the constituents. This feature of solid state reactions is clearly brought out in topochemical and topotactic reactions. Most of the photochemical transformations of organic solids are controlled by crystal chemistry. We shall discuss organic solid state reactions in some detail and devote our attention to intercalation reactions of solids that have gained considerable importance recently. We shall briefly deal with some aspects of catalysis to point out how solid state chemistry plays a role in this crucial branch of chemical technology.
