Infrared spectra of inorganic compounds
01 Jan 1971-pp 1-18
TL;DR: In this article, the experimental, theoretical, and empirical correlations between functional organic groups and the infrared spectrum were discussed and many examples of spectra of inorganic compounds in the solid phase were presented.
Abstract: This chapter discusses the experimental, theoretical, and empirical correlations between functional organic groups and the infrared spectrum. The application of infrared spectroscopy to the identification of inorganic compounds is less successful. In obtaining infrared spectra of inorganic solids, an experimental complication arises from possible chemical reaction between the inorganic compound and the infrared window material or support medium. The chapter presents many examples of spectra of inorganic compounds in the solid phase. The majority of these compounds are crystalline solids in which the crystallographic unit cell contains several polyatomic ions or molecules. Optical modes called lattice modes of vibration result from the motion of one polyatomic group relative to another within the unit cell. Lattice modes occur in the region 400–10 cm −1 and are characteristic of specific crystal geometry. They are used as fingerprints for an inorganic compound in much the same way as the internal modes of vibration of organic compounds are used in the region 4000–400 cm −1 .
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TL;DR: In this paper, photo-induced superhydrophilicity was used on the surface of a wide-band gap semiconductor like titanium dioxide (TiO 2 ) for photocatalytic activity towards environmentally hazardous compounds.
4,241 citations
TL;DR: In this article, the drying process, the atmosphere during the carbonisation, the chemical state of the activating agents (NaOH, KOH and Na 2 CO 3 ) and the chemical reactions occurring during the heat treatment have been analyzed to deep into the fundamental of the knowledge of this chemical activation process.
989 citations
TL;DR: A review of the literature on grain refinement by heterogeneous nucleation and alloying can be found in this paper, where the types of grain refiner, Al-Ti-B master alloys in particular, and their methods of manufacture are discussed.
Abstract: Grain refinement of aluminium and its alloys is common industrial practice. The field has been extensively investigated by many workers over the past 50 years, not only to develop efficient grain refiners for different aluminium alloys, but also to achieve an understanding of the mechanism of grain refinement. The present review confines itself to the literature on grain refinement by heterogeneous nucleation and alloying. Initially, the fundamentals of grain refinement by inoculants are outlined. The types of grain refiner, Al-Ti-B master alloys in particular, and their methods of manufacture are next discussed. The grain refining tests to assess the efficiency of the grain refiners and the grain refining behaviour of aluminium alloys are also discussed in brief. The performance of a grain refiner, as well as the response of an aluminium alloy to grain refinement, is influenced by the microstructure of the grain refiner as controlled by the process parameters involved in its preparation and the alloying elements present in the aluminium alloy. The roles of these factors, and particularly the roles of poisoning elements such as Si, Cr, Zr, Li, are reviewed. The paper also reviews the mechanisms of grain refinement, the fading and poisoning phenomena, and the trends in the development of new grain refiners for aluminium alloys containing poisoning elements.
700 citations
TL;DR: In this article, the authors used Diffuse reflectance spectroscopy (DRIFTS) to monitor the in situ oxidation of carbons after a heat treatment at 1230K under flowing Ar or H2 to remove sulfur impurities and provide oxygen-free carbon surfaces.
556 citations
TL;DR: In this article, two possible mechanisms for the formation of alkyl carbonates are discussed: nucleophilic reaction of propylene carbonate with basic species such as OH−, and one-electron reduction by lithium metal, followed by free radical termination reactions.
Abstract: FTIR, IR, and XPS have been used to study the films formed on lithium in propylene carbonate solutions of ,, and . Over a range of conditions, the main components detected in the initial surface films were lithium alkyl carbonates . Another alkyl carbonate solvent, diethyl carbonate, was found to react with lithium to form lithium ethyl carbonate, . In addition to solvent reduction, XPS measurements gave indication of salt reduction reactions. , , and were reduced by lithium to form halide ions, which were detected on the lithium surface. Two possible mechanisms for the formation of alkyl carbonates are discussed. One is the nucleophilic reaction of propylene carbonate with basic species such as OH−, while the other involves one‐electron reduction of propylene carbonate by lithium metal, followed by free radical termination reactions. When high concentrations of water were present, lithium carbonate was formed by further reaction of the alkyl carbonates with water. On lithium surfaces without a mechanically stable surface film, such as those of lithium/mercury amalgams, the reduction reaction is believed to proceed by an overall two‐electron process, and the primary product is lithium carbonate.
532 citations
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TL;DR: In this paper, the distribution of point symmetries within space groups and the population of the unit cell were used to derive selection rules for Raman and infra-red spectra of crystals.
Abstract: A method is described that permits deduction of selection rules for Raman and infra‐red spectra of crystals from a knowledge of just the space group designation and the population of the unit cell. When implemented by an appendix to this article showing, in a convenient arrangement, the distribution of point symmetries within space groups the method can be applied by a user familiar with point group manipulation but having no special knowledge of space groups. There are no selection rules operating in the liquid state. Some tentative qualitative conclusions are drawn concerning the relative intensities of certain kinds of components appearing in spectra of condensed systems. Sharpened selection rules are expected, and have been observed by others, to operate for single crystals containing non‐rotating molecules when these are given special orientations in the light path. These special orientations and the appropriate selection rules can be predicted from information mentioned above along with inspection of the external form of a crystal. All procedures have a desirable advantage of simplicity over prior ones directed toward the same ends.
393 citations
TL;DR: In this paper, the vibrational and rotational transitions in a molecule may also be induced in another way by the scattering of light under certain conditions, the electric field of an incident radiation may induce a dipole moment and the molecule can therefore interchange energy with the photon.
Abstract: Publisher Summary This chapter illustrates the spectra resulting from vibrational transitions in solids It describes the vibrational part of the internal energy The transitions between different vibrational energy levels give rise to the near infrared emission or absorption spectra and are stimulated provided there is a change of dipole moment connected with such a transition The factor group analysis and the normal modes of oscillation of brucite are discussed in the chapter The chapter describes the vibrational spectra of a number of crystals of varying composition and structure The vibrational and rotational transitions in a molecule may also be induced in another way by the scattering of light Under certain conditions, the electric field of an incident radiation may induce a dipole moment and the molecule can, thus, interchange energy with the photon This exchange produces the Raman spectrum that in its structure resembles the infrared spectrum, although the two originate from two different processes—namely light scattering and absorption or emission of radiation
94 citations