Diffraction infrared

A variety of instmmental techniques may be used to determine mineral content. Typically the coal sample is prepared by low temperature ashing to remove the organic material. Then one or more of the techniques of x-ray diffraction, infrared spectroscopy, differential thermal analysis, electron microscopy, and petrographic analysis may be employed (7). 

Biological, chemical. X-ray diffraction, infrared absorption, e.s.r., n.m.r., luminescence, and quantum studies show that dimer formation is universally observed in irradiated frozen solutions of thymine, thymidine, uridine, thymidylic acid and related compounds, and in DNA [560—576]. The purines of DNA, on the other hand, are little affected [577, 578]. Thymine dimers obtained in frozen solution can be converted to the original monomers by ultraviolet... 

In this study, the structure of the vanadium species supported on AIPO -S molecular sieve has been studied by X-ray diffraction, infrared, diffused reflectance, and EPR spectroscopy, temperature programmed desorption, and their properties compared with those of VAPO -S. 

The understanding of the reduction process of sulfur requires the identification of the reduced forms of sulfur, that is, polysulfides or S . The phase diagrams of M2S —Sg systems (where M is an alkali-metal cation) have been reviewed [23], as also the properties of polysulfide melts [24]. Many polysulfides have been characterized in the solid state by x-ray diffraction, infrared and Raman spectroscopy [25]. The identification of polysulfides in solution is often rather difficult. The reason is that the dissolution of a M2S polysulfide leads, for most of them, to a disproportionation process of the type ... 

Chemical State Radiation Reflection or Diffraction Infrared attenuated total reflectance (ATR) Infrared reflectance Ultraviolet spectroscopy X-ray diffraction Resonant Response NMR EPR... 

Annenkova et al. (105) studied both the physicochemical and catalytic properties of the Bi-Fe-Mo oxide system. The X-ray diffraction, infrared spectroscopic, and thermographic measurements indicated that the catalysts were heterogeneous mixtures consisting principally of ferric molybdate, a-bismuth molybdate, and minor amounts of bismuth ferrite and molybdenum trioxide. The Bi-Fe-Mo oxide catalysts were more active in the oxidation of butene to butadiene and carbon dioxide than the bismuth molybdate catalysts. The addition of ferric oxide to bismuth molybdate was also found to increase the electrical conductivity of the catalyst. 

A.J. Bienko et al., Low barrier hydrogen bond in protonated proton sponge. X-ray diffraction, infrared, and theoretical ab initio density functional theory studies. J. Chem. Phys. 119, 4313 4319 (2003)... 

Osmium tetroxide reacts with CsF or RbF in water forming M2[0s04F2] H20 (M = Cs, Rb) which were characterized by elemental analysis, X-ray powder diffraction, infrared spectroscopy and thermogravimetric analysis [353]. Based on vibrational spectroscopy, the 0s04F22 anion is considered to possess a m-difluoro arrangement. Osmium Lm EXAFS data have been obtained for Cs2[0s04F2] giving values for the 0s=0 and Os—F bond distances [354]. 

Lager G. A., Armbruster T., RoteUa F. J., and Rossman G. R. (1989) OH substitution in garnets X-ray and neutron diffraction, infrared, and geometric-modelling studies. Am. Mineral. 74, 840-851. 

Methodology for studying the polymorphism of fats, among which thermal analysis, most typically, differential scanning calorimetry (DSC), X-ray diffraction (XRD), neutron diffraction, infrared absorption spectroscopy, and nuclear magnetic resonance (NMR), are briefly mentioned here. 

Samples were characterized using conventional techniques (X-Ray Diffraction, Infrared Spectroscopy,. ..). The absence of highly dispersed oxide particles was deduced from Diffuse Reflectance Spectra. 

In recent years other methods for the detection of the onset or the progress of thermally dependent reactions have been employed with increasing frequency. The measurements used include those of conductivity, density, optical density and color, volume changes, electron and x-ray diffraction, infrared absorption, nuclear magnetic resonance and various others 24, 32,33). 

Internal structure (unit cell) can be different in crystals that are chemically identical. This is called polymorphism. Polymorphs can vary substantially in physical and chemical properties such as bioavailability and solubility. They can be identified by analytical techniques such as X-ray diffraction, infrared, Raman spectro, and microscopic techniques. For the same internal structure, very small amounts of foreign substances will often completely change the crystal habit. The selective adsorption of dyes by different faces of a crystal or the change from an alkaline to an acidic environment will often produce pronounced changes in the crystal habit. The presence of other soluble anions and cations often has a similar influence. In the crystallization of ammonium sulfate, the reduction in soluble iron to below 50 ppm of ferric ion is sufficient to cause significant change in the habit of an ammonium sulfate costal from a long, narrow form to a relatively chunky and compact form. Additional information is available in the patent literature and Table 18-4 lists some of the better-known additives and their influences. 

Tashiro, K., Kamae, T., Kobayashi, M., Matsumoto, A., Yokoi, K. and Aoki, S. (1999) Structural change in the topochemical solid-state polymerization process of diethyl ds.cis-muconate crystal. 1. Investigation of polymerization process by means of X-ray diffraction, infrared/ raman spectra, and DSC. Macromolecules, 32, 2449-2454. 

The minerals found in United States coals continue to be studied with the availability of improved instrumental procedures such as x-ray diffraction, infrared absorption, and scanning electron microscopy beyond the traditional optical and chemical mineralogical techniques as applied to thin sections, polished pellets, and isolated particles. The minerals may be grouped into the silicates (kaolinite, illite montmorillonite, and chlorite), the oxides (quartz, chalcedony, hematite) the sulfides (pyrite, marcasite, and sphalerite) the sulfates (jarosite, gypsum, barite, and numerous iron sulfate minerals) the carbonates (ankerite, calcite, dolomite, and siderite) and numerous accessory minerals (apatite, phosphorite, zircon, rutile, chlorides, nitrates, and trace minerals). 

MAN/GAL] Manceau, A., Gallup, D. L., Removal of selenocyanate in water by precipitation characterization of copper-selenium precipitate by X-ray diffraction, infrared, and X-ray absorption spectroscopy, Environ. Sci. Technol., 31, (1997), 968-976. Cited on page 297. 

Since Holmes observation of the X-ray diffraction of nylon [1], many fruitful studies have been presented using X-ray diffraction, infrared absorption and other techniques. It can be expected that solid-state NMR provides useful information about the structure and dynamics of the crystalline and noncrystalline components of polyamides [2, 3]. Actually, solid-state H, and NMR have been successfully used to clarify various crystalline and amorphous components. 

In this chapter we will consider molecular crystals with normal hydrogen bonds in which the donor A H interacts with an acceptor B. The so-called bifurcated and trifurcated H-bonds [1] as well as the new multiform unconventional H-bonds [2] are beyond the scope of the present chapter. We will focus on the proton dynamics in molecular crystals with strong and moderate H-bonds [3] in the ground electronic state. Attention will be focused on the interpretation of the structural and spectroscopic manifestations of the dynamics of the bridging proton as established in X-ray, neutron diffraction, infrared, and inelastic neutron scattering (INS) studies of H-bonded crystals. 

Crystalline borosilicate molecular sieves have been the object of an intensive investigation effort since they were reported in the open literature at the Fifth International Conference on Zeolites by Taramasso, et al. (1) A wide range of structures containing framework boron have been synthesized. The physical properties of these borosilicate molecular sieves have been studied by such techniques as X-ray diffraction, infrared and nuclear magnetic resonance spectroscopies, and temperature programmed desorption of ammonia. In addition, the catalytic performance of borosilicate molecular sieves has been reported for such reactions as xylene isomerization, benzene alkylation, butane dehydroisomerization, and methanol conversion. This paper will review currently available information about the synthesis, characterization, and catalytic performance of borosilicate molecular sieves. 

The molecular structure of 1,3,5-triazine in the gas phase was determined from electron diffraction, infrared and Raman data and 4-21G force field calculations C—N bond length = 1.338 A, C—H = 1.106A, CNC bond angle = 113.9°, NCN= 126.1°, and HCN= 116.9° <86JST(147)321>. The geometries of 1,3,5-triazine and its protonated form, along with other azines, have been fully optimized at the STO-3G, 3-21G and 6-31G levels <87JST(35)135>. 

Livingstone and Bish reported X-ray powder diffraction, infrared, thermal, chemical, optical, and physical data for a Mg-bearing theophrastite from Hagdale Quarry, Unst, held in the Scottish Mineral Collection. These authors endeavoured to establish a mineral name for the compound (Ni, Mg)(OH)2 by a submission to the IMA in late 1979. Two months later IMA received another submission for pure Ni(OH)2 [81MAR/ECO]. In the vote the Unst material and name were narrowly defeated in favour of the Greek Ni(OH)2. 

Zeolites Y dealuminated by Si/Al substitution using SiCU (DAY-S) and dealuminated thermochemically in steam (DAY-T) were investigated by X-ray powder diffraction, infrared spectroscopy and wet chemical methods. The dependence of lattice constants (a) on the molar ratio X = (1+Si/Al) show non-ideal solid solution behaviour. In a first approximation the change in a (in nm) can be described as a = 0.187x+2.412, for 0.1 < x < 0.5. For x < 0.1 the change in lattice constant saturates towards a = 2.425 nm. A similar shift in the double ring mode (wdr) is observed, tailing off. 

A number of techniques have been used to determine mineralogies of coal As discussed in a recent review (J ) the most common techniques are x-ray diffraction infrared spectroscopy optical microscopyy and electron microscopy. X-ray diffraction and infrared spectroscopy can be considered "bulk methods because they are generally best performed on the mineral-matter concentrate obtained by removal of the macerals by low-ten5>era-ture ashing ( 2 ) The microscope methods can be considered "particulate methods because mineral grains in the coal are sized and classified individually These microscope methods are usually used without separation of minerals and macerals because the coal macerals can serve as a background matrix to separate mineral particles and to provide contrast for the dimensional measurement of the particle ... 

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