Spectroscopy, Mdssbauer

Mossbauer Spectroscopy. Mdssbauer spectroscopy has been used as a powerful technique to probe the electronic structure of the five- and six-coordinate ferrous nitrosyl porphyrins. The isomer shifts of both types of complexes (5 0.35 mm s ) are similar and show temperature dependences that are consistent with a second-order Doppler effect, but are slightly smaller than those of most other iron(II) porphyrin complexes (5 0.45 mm Unlike the isomer... 

N. N. Greenwood and T. C. Gibb, Mdssbauer Spectroscopy, Chapman Hall, London, 1971, 659 pp. 

N. N. Greenwood and T. C. Gibb, Mdssbauer Spectroscopy, pp. 452-62, Chapman Hall, London, 1971. F. J. Berry, Chap. 8 in G. J. Long (ed.) Mdssbauer Spectroscopy Applied to Inorganic Chemistry, Vol. 2, Plenum Press, New York 1987, pp. 343-90. 

The stability of the electronic configuration is indicated by the fact that each element has the highest ionization energy in its period, though the value decreases down the group as a result of increasing size of the atoms. For the heavier elements is it actually smaller than for first-row elements such as O and F with consequences for the chemical reactivities of the noble gases which will be considered in the next section. Nuclear properties, particularly for xenon, have been exploited for nmr spectroscopy and Mdssbauer... 

By heating the metal with appropriate oxides or carbonates of alkali or alkaline earth metals, a number of mixed oxides of Ru and Os have been made. They include NasOs Og, LifiOs Og and the ruthenites , M Ru 03, in all of which the metal is situated in octahedral sites of an oxide lattice. Ru (octahedral) has now also been established by Ru Mdssbauer spectroscopy as a common stable oxidation state in mixed oxides such as Na3Ru 04, Na4Ru2 07, and the ordered perovskite-type phases M Ln Ru Og. 

Soluble pigments The most important pigments in this class are the metallic chromates, which range in solubilities from 17 0 to 0-00005 g/1 CrO . An examination has recently been carried out of the mechanism of inhibition by chromate ions and it has been shown by chemical analysis of the stripped film, Mdssbauer spectroscopy and electron microprobe analysis that the air-formed film is reinforced with a more protective material in the form of a chromium-containing spinel (Chapter 17). The situation is, however, complicated by the possibility that some chromates, particularly the basic ones, may inhibit through the formation of soaps. There is evidence that lead chromate can function in this way. 

Characterization of Supported Iron Oxide Particles Using Mdssbauer Spectroscopy and Magnetic Susceptibility... 

Mgssbauer Spectroscopy. All details of the Mdssbauer spectroscopy studies are described elsewhere (25,27). This includes descriptions of the spectrometer, situ cells, and the computer program used to analyze the MCssbauer spectra. 

Oosterhuis, IV. T. The Electronic State of Iron in Some Natural Iron Compounds Determination by Mdssbauer and ESR Spectroscopy. Vol. 20, pp. 59-99. 

The previous chapters are exclusively devoted to the measurements and interpretation of Fe spectra of various iron-containing systems. Iron is, by far, the most extensively explored element in the field of chemistry compared with all other Mdssbauer-active elements because the Mossbauer effect of Fe is very easy to observe and the spectra are, in general, well resolved and they reflect important information about bonding and structural properties. Besides iron, there are a good number of other transition metals suitable for Mossbauer spectroscopy which is, however, less extensively studied because of technical and/or spectral resolution problems. In recent years, many of these difficulties have been overcome, and we shall see in the following sections a good deal of successful Mossbauer spectroscopy that has been performed on compounds of... 

In Table 7.1 at the end of the book), nuclear data are collected for those Mdssbauer transitions of transition metal nuclides that are used in Mossbauer spectroscopy. The symbols used in this table have the following meaning ... 

The relatively low Lamb-Mossbauer factors encountered in Ni Mdssbauer spectroscopy (a diagram showing the Lamb-Mdssbauer factor as a function of Debye temperature is given in [3]) require the cooling of both source and absorber, preferentially to temperatures S80 K. The cryogenic systems have been described, e.g., in [2, 4]. 

Practical Aspects of Mdssbauer Spectroscopy with Osmium... 

Dunlap, B.D. Mdssbauer effect data index. In Stevens, J.G., Stevens, V.E. (eds.) An Introduction to Electric Quadrupole Interactions in Mdssbauer Spectroscopy. Adam Hilger, London (1972)... 

Since in general the nuclear g factors are different for ground and excited states of a Mdssbauer nucleus, the spin state must be quoted when giving numerical values for A in energy (which, however, is usually not necessary for NMR spectroscopy or other ground-state techniques). Thus, for a comparison of A values obtained from Mdssbauer and NMR or ENDOR spectra, usually the ground state is considered. 

The ground- and excited-state magnetic moments ji are tabulated as /ig = 0.09062(3) n.m. (nuclear magnetons, /i ) and jig, = 0.1549 n.m., respectively (see Table Properties of Isotopes Relevant to Mdssbauer Spectroscopy provided by courtesy of Professor J. G. Stevens, Mdssbauer Effect Data Center, cf. CD-ROM). Considering that nuclear magnetic moments are given by the relation p, = giPj I, the nuclear g factors for Ee with /g = 1/2 and 1 = 3/2 are gg = 0.09062 X 2 and ge = 0.1549 x 2/3. With these values and taken from... 

Active centers, nature of, 10 96 Active site, 27 210-221 in catalysts, 17 103-104, 34 1 for olefin chemisorption, 17 108-113 dual-site concept, 27 210 electrical conductivity, 27 216, 217 ESCA, 27 218, 219 ESR, 27 214-216 infrared spectroscopy, 27 213, 214 model, 27 219-221 molybdena catalyst, 27 304-306 Mdssbauer spectroscopy, 27 217, 218 nonuniform distribution, transport-limited pellets, 39 288-291... 

Carl W. Seidel During this discussion I hope that the panel and the audience will comment on the future of Mdssbauer spectroscopy in chemistry, both as an investigative tool for different elements and as to the type of information that is or may be available from Mossbauer spectroscopy. We will begin with questions on Dr. Herberts paper. 

Below is a list of selected references on Mdssbauer spectroscopy for additional reading. 

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