X-Ray and uv photoelectron spectra of FeO, Fe2O3, and Fe3O4 have been studied along with those of a few model compounds. It has been possible to assign distinct bands due to Fe2+ and Fe3+ in the 3d, 3p, 3s, and 2p bands of Fe3O4. The spectra of Fe3O4 do not show major changes through the Verwey transition.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInfrared Spectra of Organic AzidesEugene. Lieber, C. N. R. Rao, T. S. Chao, and C. W. W. HoffmanCite this: Anal. Chem. 1957, 29, 6, 916–918Publication Date (Print):June 1, 1957Publication History Published online1 May 2002Published inissue 1 June 1957https://pubs.acs.org/doi/10.1021/ac60126a016https://doi.org/10.1021/ac60126a016research-articleACS PublicationsRequest reuse permissionsArticle Views7710Altmetric-Citations121LEARN 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
Conversion of solar energy to useful chemicals has become necessary for finding solutions to energy and environmental issues. One of the means is to use of solar energy for the reduction of water to generate hydrogen or for the reduction of CO[Formula: see text] to useful chemicals. In spite of substantial effort, the discovery of stable and efficient photocatalysts remains a challenge, although some encouraging results have been reported. In this article, we provide a brief perspective of the current status of solar water splitting and reduction of CO[Formula: see text].
Two-dimensional arrays of Pd nanocrystals of varying diameters (1.8−6.0 nm) have been obtained after thiolization with alkane thiols of different chain lengths (C4−C16). The stability and structure of these arrays have been explained in terms of the ratio of the particle diameter (d) and the alkane chain length (l). The experimental d−l phase diagram finds support from model calculations, which treat the thiolized nanocrystals as soft spheres. Generally, a d/l value between 1.5 and 3.8 gives crystalline arrays extended over several microns. For d/l values smaller than 1.5 and greater than 4.0, the nanocrystal arrays are disordered or form low-order structures.
Two new three-dimensional zinc phosphates I, [NH(CH2)2NH2(CH2)2NH3]2+[Zn5(PO4)4]2-, and II, [CN5H6]+[Zn2(PO4)(HPO4)]-, where the structure-directing organic amine acts as a ligand, have been synthesized hydrothermally. Crystal data for I: a=27.071(2), b=5.215(1), c=17.920(1) Å, β=130.3(1)°; U=1930.9(3) Å3; space group=Cc (no. 9); Z=4; M=811.01; Dcalc=2.789 g cm-3; MoKα and for II: a=8.089(1), b=12.771(1), c=10.067(1) Å, β=105.3(1)°; U=1000.3(2) Å3; space group=P21/n (no. 14); Z=4; M=409.8; Dcalc=2.713 g cm-3; MoKα. Compound I is novel in the sense that it is dominated by the presence of a large number of three-coordinated oxygen atoms (25%), leading to the formation of infinite Zn–O–Zn chains. The presence of a distorted bipyramidal ZnO3N2 unit as well as a 2-membered ring in II is noteworthy. These structures are formed by the networking of ZnO4, ZnO3N, PO4 and ZnO3N2 moieties, leading to the formation of three-dimensional structures possessing channels with I forming a 10-membered one-dimensional channel system and II forming two 8-membered channels.
No abstract is provided for this article.
Core–shell nanoparticles based on metallic ReO3 nanoparticles have been prepared for the first time. The nanoparticles with the metallic shell viz. ReO3@Au and ReO3@Ag were prepared by the reduction of metal salts over ReO3 nanoparticle seeds. ReO3@SiO2 and ReO3@TiO2 core–shell nanoparticles were prepared by the hydrolysis of the organometallic precursors over the ReO3 nanoparticles. The core–shell nanoparticles have been characterized by transmission electron microscopy, optical absorption spectroscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and Raman spectroscopy. The ReO3@Au and ReO3@Ag core–shell nanoparticles show composite plasmon absorption bands comprising contributions from both ReO3 and Au (Ag) whereas ReO3@SiO2 and ReO3@TiO2 show shifts in the plasmon bands depending on the refractive index of the shell material.
The metal–insulator transition, a quantum phase transition signifying the natural transformation of a metallic conductor to an insulator, continues to be the focus of intense inquiry and debate. The first discussion of the heuristic differences between metals and insulators, and implicitly the critical conditions for the transition between these canonical electronic regimes, dates back to the dawn of the twentieth century. As we approach the end of the century, the precise nature of the metal–insulator transition remains one of the major intellectual challenges in condensed matter science. In this article we present a brief introduction to just some of the key underlying features of this enduring physical phenomenon. The following articles and discussion present a detailed current account of the many facets of the science of the metal–insulator transition.
The n=1, 2 and 3 members of the Bi2(Ca, Sr)n+1CunO2n+4 series of superconductors have been synthesized and characterized by a variety of techniques including electrical resistivity, magnetic susceptibility and non-resonant microwave absorption. Based on studies with a number of compositions, the T c ranges for the n=1, 2 and 3 members are suggested to be 60±20 K, 82±8 K, and 107±3 K, the rather broad ranges arising from differences in sample stoichiometry and homogeneity. Electron spectroscopic studies show that Cu is mainly in the 2 + and 1 + states suggesting the importance of oxygen holes.
The discovery of the amazing properties of graphene has stimulated exploration of single- and few-layer structures of layered inorganic materials. Of all the inorganic 2D nanosheet structures, those of MoS2 have attracted great attention because of their novel properties such as the presence of a direct bandgap, good field-effect transistor characteristics, large spin–orbit splitting, intense photoluminescence, catalytic properties, magnetism, superconductivity, ferroelectricity and several other properties with potential applications in electronics, optoelectronics, energy devices and spintronics. MoS2 nanosheets have been used in lithium batteries, supercapacitors and to generate hydrogen. Highlights of the impressive properties of MoS2 nanosheets, along with their structural and spectroscopic features are presented in this Letter. MoS2 typifies the family of metal dichalcogenides such as MoSe2 and WS2 and there is much to be done on nanosheets of these materials. Linus Pauling would have been pleased to see how molybdenite whose structure he studied in 1923 has become so important today.
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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.
