TY - JOUR A1 - Rohde, H. A1 - Menzel, Michael A1 - Renz, F. A1 - Filippou, A.C. T1 - Investigation of Mo- and W-stannylidyne complexes by Mössbauer spectroscopy N2 - Systematic 119mSn-Mössbauer spectroscopy studies of three different types of five and six coordinated molybdenum and tungsten stannylidyne complexes are presented. The measured isomer shifts (IS) range from 2.38 to 2.50 mm/s and the quadrupole splittings (QS) from 1.8 to 2.8 mm/s. The values are dependent on the metal centre, the ligand sphere and the charge of the complexes. The influence of the neighbouring metal atoms (Mo, W) and their coordination sphere on the electron density at the tin atom is observed and will be discussed. KW - Molybdenum KW - Tungsten KW - Stannylidyne complexes KW - Phosphane complexes KW - 119mSn-Mössbauer spectroscopy PY - 2008 DO - https://doi.org/10.1007/s10751-008-9821-7 SN - 0304-3843 SN - 1572-9540 VL - 185 IS - 1-3 SP - 129 EP - 132 PB - Kluwer CY - Dordrecht AN - OPUS4-18623 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Renz, F. A1 - Zaba, C. A1 - Roßberg, L. A1 - Jung, S. A1 - Klein, M. A1 - Klingelhöfer, G. A1 - Wünsche, A. A1 - Reinhardt, S. A1 - Menzel, Michael T1 - Spin transition in heptanuclear star-shaped iron(III)-antimony(V) NCS- and CN-bridged compounds N2 - The precursor [FeIII(L)Cl] (LH2 = N,N'-bis(2'-hydroxy-benzyliden)-1,6-diamino-3-azahexane) has been prepared and Mössbauer spectroscopy assigned a high-spin (S = 5/2) state at room temperature. The precursor is combined with the bridging units [SbV(X)6]- (X = CN-, NCS-) to yield star-shaped heptanuclear clusters [(LFeIII-X)6SbV]Cl5. The star-shaped compounds are in general high-spin systems at room temperature. On cooling to 20 K some of the iron(III) centers switch to the low-spin state as indicated by Mössbauer spectroscopy, i.e. multiple electronic transitions. While the cyano-bridged complex performs a multiple spin transition the thiocyanate-compound shows no significant population at both temperatures. KW - Heptanuclear KW - High-spin molecule KW - SbV KW - Multistability KW - Multiple spin transition PY - 2009 DO - https://doi.org/10.1016/j.poly.2008.12.027 SN - 0277-5387 VL - 28 IS - 9-10 SP - 2036 EP - 2038 PB - Elsevier CY - Amsterdam [u.a.] ; Jena AN - OPUS4-19659 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Balle, P. A1 - Geiger, B. A1 - Klukowski, D. A1 - Pignatelli, M. A1 - Wohnrau, S. A1 - Menzel, Michael A1 - Zirkwa, I. A1 - Brunklaus, G. A1 - Kureti, S. T1 - Study of the selective catalytic reduction of NOx on an efficient Fe/HBEA zeolite catalyst for heavy duty diesel engines KW - SCR KW - BEA KW - Zeolite KW - Fe KW - Active sites KW - Diesel engine KW - Hydrothermal aging KW - SO2 stability PY - 2009 DO - https://doi.org/10.1016/j.apcatb.2009.06.031 SN - 0926-3373 SN - 1873-3883 VL - 91 IS - 3-4 SP - 587 EP - 595 PB - Elsevier CY - Amsterdam AN - OPUS4-19798 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stößer, R. A1 - Feist, M. A1 - Menzel, Michael A1 - Nofz, Marianne T1 - Fe3+ ions acting as probes and agents in aggregation processes and solid-state reactions in AlO(OH)/Al2O3 matrices N2 - The fate of doped iron species during various mechanically and thermally initiated redox reactions and aggregation processes in crystalline and amorphous AlO(OH) or Al2O3 matrices was investigated. The amorphization of the matrix was performed by chemical (i.e., via sol-gel processes) or mechanochemical treatment (high-energy ball milling). Thermal analysis, coupled with mass spectrometry (TA-MS), Mössbauer spectroscopy, and electron spin resonance (ESR), was used. The TA under various gas atmospheres allowed preparing samples under a controlled temperature regime, together with a controlled gas influence. Both the effect of mechanical activation and the influence of the iron doping could be followed macroscopically via the down-shift of the peak temperature of the corundum formation. The ESR data characterize the Fe3+ ions and their interaction with the magnetic surrounding based on the fine structure parameters. The Mössbauer data allowed the characterization of the Fe(0), Fe2+, and Fe3+ species, together with providing information about their coordinative surrounding. Both methods provided general complementary spectroscopical information. Unexpectedly, (FeOx)n and (FexAl1-x)2O3 aggregates could also be detected in the range of low Fe concentrations. It was demonstrated that even in the low-level doped systems [(FexAl1-x)2O3 with x ≥ 0.01], all the essential spectroscopic phenomena occur. At higher Fe concentrations, they were discovered to be caused by magnetic and spin exchange interactions as well as by solid-state reactions during and after the mechanical activation. PY - 2010 DO - https://doi.org/10.1111/j.1551-2916.2009.03596.x SN - 0002-7820 SN - 1551-2916 VL - 93 IS - 5 SP - 1447 EP - 1456 PB - Blackwell Publishing CY - Malden AN - OPUS4-21235 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jung, S. A1 - Renz, F. A1 - Klein, M. A1 - Menzel, Michael A1 - Boca, R. A1 - Stößer, R. T1 - Molecular switching in iron complexes bridged via tincyanides observed by Mössbauer and ESR spectroscopy N2 - The precursor [FeIII(L)Cl] (LH2 = N,N'-bis(2'-hydroxy-3'-X-benzyliden)-1,6-diamino-3-N-hexane) is a high-spin (S = 5/2) complex (with X = -CH3, -O-CH3). This precursor is combined with the bridging unit [SnIV(CN)4] to yield star-shaped pentanuclear clusters, [(L-X-FeIII)4Sn(CN)4]Cl4 57Fe-Mössbauer, 119mSn-Mössbauer, and ESR spectroscopy are used to study our samples. For X = -CH3 the 57Fe-Mössbauer data show a multiple spin transition between iron(III) in the high-spin and low-spin state. Changing the functional group from X = -CH3 to X = -O-CH3 turns the switchability off. KW - Switching iron complexes KW - Spin-transition KW - Mössbauer spectroscopy KW - ESR-spectroscopy PY - 2010 DO - https://doi.org/10.1088/1742-6596/217/1/012027 SN - 1742-6588 SN - 1742-6596 VL - 217 IS - 1 / 012027 SP - 1 EP - 6 PB - IOP Publ. CY - Bristol, UK AN - OPUS4-22561 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stößer, R. A1 - Menzel, Michael A1 - Feist, M. T1 - The fate of Fe3+ ions in the system {AlO(OH)-xerogel/Fe-compounds} after mechanical activation and different thermal treatments studied by Mössbauer, ESR spectroscopy and thermal analysis KW - Mössbauer KW - ESR KW - Thermal analysis KW - High energy ball milling KW - Activation/deactivation processes KW - Local mechano-chemical reactions KW - Heterogeneous redox reactions PY - 2009 DO - https://doi.org/10.1007/s10751-009-9920-0 SN - 0304-3843 SN - 1572-9540 VL - 190 IS - 1-3 SP - 43 EP - 49 PB - Kluwer CY - Dordrecht AN - OPUS4-19478 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stößer, R. A1 - Menzel, Michael A1 - Feist, M. A1 - Nofz, Marianne A1 - Renz, F. T1 - Competing redox reactions in Fe-containing AlO(OH) and Al2O3 matrices: A combined investigation by Mössbauer, ESR spectroscopy and thermal analysis N2 - The investigation of iron-doped AlO(OH)/Al2O3 systems revealed that the combined employment of Mössbauer and ESR spectroscopies together with thermal analysis yields meaningful data with complementary information. This mutual complementarity is based on the coexistence of Fe point defects with the corresponding aggregated FeOx species which has been observed even for very low Fe concentrations. Competing redox processes between the dopant, the AlOx matrix, and the gas atmosphere during the thermal treatment enable the generation of solid phases exhibiting specific chemical properties. The entire reaction process is influenced by a specific mechanical and thermal pre-treatment that affects predominantly oxydative processes in the matrix. A protecting influence of the matrix preventing further reductive attack of the Fe3+ Fe2+ ions by hydrogen has been established. KW - Mössbauer KW - ESR spectroscopy KW - Thermal analysis KW - Al2O3 KW - Magnetite KW - Fe(0) KW - Fe(2+) KW - Fe(3+) PY - 2010 UR - http://iopscience.iop.org/1742-6596/217/1/012028/pdf/1742-6596_217_1_012028.pdf DO - https://doi.org/10.1088/1742-6596/217/1/012028 SN - 1742-6588 SN - 1742-6596 VL - 217 IS - 1 SP - 012028-1 - 012028-5 PB - IOP Publ. CY - Bristol, UK AN - OPUS4-21876 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maltsev, Yuri A1 - Maltsev, S. A1 - Menzel, Michael A1 - Rogozev, B. A1 - Silvestrov, A. T1 - Two-Dimensional Mössbauer Spectra N2 - To decrease the spectra measurement time in Mössbauer spectroscopy a new data acquisition system was proposed, which allows to collect data as a two-dimensional distribution. KW - Data acquisition KW - Signal processor KW - Two-dimensional Mössbauer spectrum PY - 2004 DO - https://doi.org/10.1023/B:HYPE.0000043204.05421.b5 SN - 0304-3843 SN - 1572-9540 VL - 156/157 SP - 27 EP - 30 PB - Kluwer CY - Dordrecht AN - OPUS4-4578 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mehner, Hartmut A1 - Menzel, Michael A1 - Nofz, Marianne T1 - Laboratory Intercomparison on the Determination of the Fe(II)/Fe(III) Ratio in Glass Using Mössbauer Spectroscopy N2 - The Mössbauer community all over the world was given the opportunity to determine the Fe(II)/Fe(III) ratio in 4 glass samples of different total iron content, to classify themselves with respect to their measurement technique and especially to their kind of evaluation. KW - Mössbauer spectroscopy KW - Iron KW - Glass KW - Intercomparison KW - Fe(II)/Fe(III) ratio PY - 2004 DO - https://doi.org/10.1023/B:HYPE.0000043252.55048.63 SN - 0304-3843 SN - 1572-9540 VL - 156-157 SP - 347 EP - 352 PB - Kluwer CY - Dordrecht AN - OPUS4-4579 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lawaczeck, R. A1 - Menzel, Michael A1 - Pietsch, H. T1 - Superparamagnetic iron oxide particles: contrast media for magnetic resonance imaging N2 - The mainstream magnetic iron oxide particles used as contrast media for magnetic resonance (MR) imaging are composed of a magnetic iron oxide core surrounded by a dextran or carboxydextran coat. The core size ranges from 2 nm to less than 10 nm, and the hydrodynamic diameter ranges from 20 nm to about 120 nm. The coat prevents aggregation and sedimentation of the particles in aqueous solutions, achieves high biological tolerance, and prevents toxic side effects. Two kinds of particles are considered: (i) large particles (>30 nm), called superparamagnetic iron oxide particles (SPIOs) for liver imaging; (ii) smaller particles (<30 nm hydrodynamic diameter), called ultrasmall SPIOs (USPIOs), e.g. for MR angiography. To characterize the particles, Mössbauer spectra are presented for the two particle ensembles. These spectra allow insight into the magnetic coupling, the valency of the iron ions and a rough estimate of the core size to be deduced. On the basis of the concentration dependence of the MR signal intensities, two applications are discussed together with two representative clinical examples. KW - Superparamagnetic KW - Iron oxide particles KW - MR imaging KW - Contrast media PY - 2004 DO - https://doi.org/10.1002/aoc.753 SN - 0268-2605 SN - 1099-0739 VL - 18 SP - 506 EP - 513 PB - Longman CY - Harlow AN - OPUS4-4580 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mehner, Hartmut A1 - Menzel, Michael A1 - Berndt, H. A1 - Claus, P. T1 - Mössbauer studies of platinum and rhodium catalysts promoted by tin T2 - International Conference on Applications of the Mössbauer Effect (ICAME '97) ; in memoriam of Professor Jacques CY - Rio de Janeiro, Brazil DA - 1997-09-14 PY - 1998 SN - 0304-3843 SN - 1572-9540 VL - 113 IS - 1-4 SP - 92 EP - 95 PB - Kluwer CY - Dordrecht AN - OPUS4-6932 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maltsev, Y. A1 - Mehner, Hartmut A1 - Menzel, Michael A1 - Rogozev, B. T1 - Precision in Mössbauer Spectroscopy N2 - In this paper the factors which are responsible for precision and reliability of the experimental data are discussed. The detectors of different types are compared with respect to the precision of the final results. It is shown that the use of resonance detectors gives the best results in most cases of the Sn-119m Mössbauer spectroscopy. The estimation of spectral line distortion caused by a short distance between source and detector is presented. Different procedures of velocity scale calibration are discussed. It has to be underlined that Kuprijanov's method of the velocity scale calibration gives the most reliable and fast results. T2 - 5th International Symposium on the Industrial Applications of the Mössbauer Effect (ISIAME) CY - Virginia Beach, VA, USA DA - 2000-08-13 PY - 2002 DO - https://doi.org/10.1023/A:1021203718759 SN - 0304-3843 SN - 1572-9540 VL - 139-140 IS - 1-4 SP - 679 EP - 684 PB - Kluwer CY - Dordrecht AN - OPUS4-2257 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heinrich, F. A1 - Schmidt, C. A1 - Löffler, E. A1 - Menzel, Michael A1 - Grünert, W. T1 - Fe-ZSM-5 Catalysts for the Selective Reduction of NO by Isobutane - The Problem of the Active Sites N2 - Relations between the structure of Fe–ZSM-5 catalysts prepared by interaction of FeCl3 with H–ZSM-5 and their catalytic behavior in the SCR of NO by isobutane were investigated by combining results of catalytic studies (1000 ppm NO, 1000 ppm isobutane, and 2% O2 in He, 30,000 h-1) and of physicochemical characterization (XRD, EXAFS, Mössbauer spectroscopy, TPR, IR, XPS). By variation of the preparation conditions (method of FeCl3 introduction—chemical vapor deposition or solid-state ion exchange, washing intensity, calcination regime) and of the matrix (H–ZSM-5 with normal and high defect density), Fe–ZSM-5 materials with strongly varying properties (aggregation degree of the Fe phase, acidity) were obtained. Significant discrepancies between conclusions derived from EXAFS, TPR, and Mössbauer spectroscopy were ascribed to a preference of Mössbauer spectroscopy for the detection of aggregated phases and a high defectivity of Fe oxide clusters formed upon calcination. The critical step for the preparation of a highly disperse Fe phase is extensive washing after Fe introduction. The catalytic behavior of overexchanged Fe–ZSM-5 materials prepared by interaction of FeCl3 with H–ZSM-5 of normal defect density was not influenced by aggregation of a significant part of the Fe phase. The comparison of their catalytic properties with those of a Fe2O3/H–ZSM-5 mechanical mixture and of catalysts prepared by aqueous ion exchange or by CVD of FeCl3 into H–ZSM-5 of high defect density implies that the particular activity of overexchanged Fe–ZSM-5 arises from minority sites. In these, the Fe ions are probably isolated. Other Fe sites of low nuclearity appear to add to the activity. The poor SCR performance (at a given ability for isobutane activation) of Fe–ZSM-5 prepared with a defective ZSM-5 matrix may indicate that the Fe sites which provi de the particular activity of overexchanged Fe–ZSM-5 require the cooperation of acidic sites. KW - deNOx KW - Hydrocarbons KW - Isobutane KW - Fe-ZSM-5 KW - EXAFS KW - Mössbauer spectroscopy KW - Temperature-programmed reduction PY - 2002 DO - https://doi.org/10.1006/jcat.2002.3775 SN - 0021-9517 SN - 1090-2694 VL - 212 SP - 157 EP - 172 PB - Acad. Press CY - San Diego, Calif. AN - OPUS4-2258 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmauke, T. A1 - Menzel, Michael A1 - Roduner, E. T1 - Magnetic properties and oxidation state of iron in bimetallic Pt-Fe/KL zeolite catalysts N2 - In view of an understanding of catalytic efficiency the electronic and magnetic state of iron in Fe/KL and the influence of Pt on these properties in Pt-Fe/KL were investigated by superconducting quantum interference device (SQUID) magnetization measurements and Mössbauer spectroscopy. After calcination in air, iron is present only as Fe3+ ions in both samples, mainly in a paramagnetic state. There is also a small antiferromagnetic contribution, probably due to iron oxide and hydroxide particles which precipitate on the outer surface of the zeolite crystallites during preparation. After reduction in H2, the behavior of both samples is predominantly superparamagnetic, but the presence of Pt increases both the saturation magnetization and the size of the residual hysteresis loop. At the same there remains a pronounced paramagnetic contribution which appears to be even slightly higher than before reduction. The interpretation is that alloy particles of metallic Pt–Fe are formed on the outer surface. Since small clusters inside the zeolite crystallites are most active for catalysis the alloy formation seems to be not of relevance for an enhancement of sulfur resistance. It was also shown that during reduction a fraction of Fe2+ is formed. The coordination of the Fe2+ ions is clearly influenced by Pt and it seems very likely that Fe2+ ions are in close contact with Pt clusters. This interaction is probably the origin of the enhanced sulfur resistance and catalytic activity in the reforming reactions. KW - Pt-Fe/KL zeolite KW - SQUID magnetization measurements KW - Mössbauer spectroscopy KW - Oxidation state of iron KW - Pt-Fe alloy PY - 2003 DO - https://doi.org/10.1016/S1381-1169(02)00522-8 SN - 1381-1169 SN - 1873-314X VL - 194 SP - 211 EP - 225 PB - Elsevier CY - Amsterdam AN - OPUS4-2296 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cieslak, J. A1 - Dubiel, S.M. A1 - Eichhorn, F. A1 - Menzel, Michael A1 - Reuther, H. T1 - Investigation of single-crystals of chromium implanted with 119Sn-ions of various energies N2 - Single-crystals of chromium doped with 10 16 119Sn ions per cm2 and energies ranging between 45 and 190 keV were investigated with conversion electron Mössbauer spectroscopy (CEMS), Auger electron spectroscopy (AES), grazing angle X-ray diffraction (GAXRD), and scanning electron microscopy (SEM). The Mössbauer spectra were found to be significantly different than those of the bulk. Both the maximum and the average hf. field values were higher by a factor of ˜3 than the corresponding quantities for the bulk. The overall shape of the spectra is also different. GAXRD study has revealed that the near-surface zone of the investigated samples has a nanocrystalline structure with the average size of grains ranging between ˜20 and ˜40 nm. The latter seems to be the main reason for the observed enhancement of the spin-density and its distortion. KW - Magnetically ordered materials KW - Crystal growth KW - Hyperfine interactions KW - Mössbauer spectroscopy PY - 2007 DO - https://doi.org/10.1016/j.jallcom.2006.07.143 SN - 0925-8388 SN - 1873-4669 VL - 442 IS - 1-2 SP - 235 EP - 238 PB - Elsevier Sequoia CY - Lausanne AN - OPUS4-15730 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Menzel, Michael A1 - Berndt, H. A1 - Mönnich, I. A1 - Lücke, B. T1 - Tin promoted palladium catalysts for nitrate removal from drinking water N2 - Hydrogenation of nitrate to nitrogen using Pd/Al2O3 catalysts promoted by a second metal offers a promising process for nitrate removal in drinking water treatment. This study was aimed to elucidate the nature and function of promoting tin species in PdSn/Al2O3 catalysts obtained in different preparation routes. On one hand, a parent Pd/Al2O3 catalyst was doped via impregnation with aqueous solutions of SnCl2 of different concentrations. On the other hand, the palladium surface of the same parent Pd/Al2O3 catalyst was modified via controlled surface reaction (CSR) with hexane solutions of Sn(C4H9)4. The structure of the different PdSn/Al2O3 catalysts was investigated by 119Sn-Mössbauer spectroscopy and by means of various chemisorption techniques (static and pulse chemisorption of H2 or CO, measurement of the differential heat of CO chemisorption, FTIR spectroscopy of CO chemisorption). Catalytic properties were studied in batch experiments under atmospheric pressure. Promoting of the Pd/Al2O3 catalyst by CSR resulted in catalysts with a significantly higher activity compared to PdSn/Al2O3 catalysts obtained via incipient wetness method. Obviously, Sn(II)-species being present in the latter in high portion inhibit the nitrate reduction on bimetallic PdSn ensembles. CO chemisorption reflected a ‘palladium site blocking’ by tin species in both kinds of catalysts and indirectly indicated the generation of palladium–tin ensembles. In case of the CSR preparation the palladium is alloyed by metallic tin. The palladium surface is diluted by tin atoms, i.e. bimetallic PdSnx ensembles are generated which are able to adsorb and activate nitrate ions. There is an optimum of tin loading, i.e. the activity decreases and the undesired ammonium production in a site reaction increases when the surface becomes too tin rich. Sn(II) species, being preferentially present in catalysts obtained by SnCl2 impregnation also strongly modify the chemisorption properties of the palladium surface, but obviously these species inhibit the nitrate reduction on the bimetallic PdSn ensembles, which are also present in these catalysts. KW - Nitrate hydrogenation KW - Drinking water treatment KW - Bimetallic catalysts KW - Characterization KW - Palladium-tin interactions PY - 2001 DO - https://doi.org/10.1016/S0926-3373(00)00225-3 SN - 0926-3373 SN - 1873-3883 VL - 30 IS - 1-2 SP - 111 EP - 122 PB - Elsevier CY - Amsterdam AN - OPUS4-1021 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Menzel, Michael A1 - Uzoukwu, B.A. A1 - Gloe, K. A1 - Rademacher, O. T1 - Synthesis, Spectroscopic, and X-Ray Diffraction Studies of cis-Dichlorobis(4-propanoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-onato) Tin(IV) N2 - Reaction between an aqueous ethanol solution of tin(II) chloride and that of 4-propanoyl-2,4-dihydro-5-methyl-2-phenyl-3 H-pyrazol-3-one in the presence of O2 gave the compound cis-dichlorobis(4-propanoyl-2,4-dihydro-5-methyl-2-phenyl-3 H-pyrazol-3-onato) tin(IV) [(C26H26N4O4)SnCl2]. The compound has a six-coordinated SnIV centre in a distorted octahedral configuration with two chloro ligands in cis position. The tin atom is also at a pseudo two-fold axis of inversion for both the ligand anions and the two cis-chloro ligands. The orange compound crystallizes in the triclinic space group P 1 with unit cell dimensions, a = 8.741(3) Å, b = 12.325(7) Å, c = 13.922(7) Å; = 71.59(4), = 79.39(3), = 75.18(4); Z = 2 and Dx = 1.575 g cm-3. The important bond distances in the chelate ring are Sn-O [2.041 to 2.103 Å], Sn-Cl [2.347 to 2.351 Å], C-O [1.261 to 1.289 Å] and C-C [1.401 Å] the bond angles are O-Sn-O 82.6 to 87.7° and Cl-Sn-Cl 97.59°. The UV, IR, 1H NMR and 119Sn Mössbauer spectral data of the compound are reported and discussed. KW - Tin (IV) complex KW - 4-Acyl-pyrazolone KW - Spectroscopy KW - Crystal structure PY - 2001 DO - https://doi.org/10.1002/1521-3749(200101)627:1<103::AID-ZAAC103>3.0.CO;2-5 SN - 0044-2313 SN - 1521-3749 SN - 0372-7874 SN - 0863-1786 SN - 0863-1778 IS - 627 SP - 103 EP - 107 PB - Wiley-VCH CY - Weinheim AN - OPUS4-1100 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mehner, Hartmut A1 - Menzel, Michael A1 - Weber, K. A1 - Regener, D. T1 - Characterization of the microstructure of high-chromium cast irons using Mössbauer spectroscopy N2 - The finish grinding process for cement materials uses ball mills with differently sized grinding balls. Because the grinding takes place through the impact and friction of the balls, balls with a high wear resistance are desirable and the materials of choice are the high-chromium white cast irons. This article examines the behavior of these cast irons when subjected to various heat treatments. The emphasis is on the dependence of the microstructure properties on the chemical composition of the alloys and the heat treatment parameters. The content of retained austenite and that of carbon in the martensite phase were determined by the use of Mössbauer spectroscopy. The results verify that a higher proportion of retained austenite with low carbon content and a martensite with higher hardness produce a material with good fracture toughness and resistance to abrasive wear. KW - High-cromium cast irons KW - White cast irons KW - Grinding process of cement materials KW - Grinding balls KW - As-cast grinding balls PY - 2001 DO - https://doi.org/10.1016/S1044-5803(01)00143-7 SN - 1044-5803 SN - 1873-4189 VL - 46 SP - 399 EP - 406 PB - Elsevier CY - New York, NY AN - OPUS4-1205 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mehner, Hartmut A1 - Menzel, Michael A1 - Müller, J.-P. A1 - Gähde, J. A1 - Güttler, B. T1 - Plasma-assisted transformation of iron surfaces into magnetite KW - Iron KW - Magnetite KW - Mössbauer spectroscopy KW - Plasma oxidation PY - 1999 SN - 0257-8972 VL - 116-119 SP - 367 EP - 369 PB - Elsevier Science CY - Lausanne AN - OPUS4-773 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Menzel, Michael A1 - Mehner, Hartmut A1 - Mönnich, I. A1 - Berndt, H. T1 - Investigation of PdSn-catalysts for nitrate removal in drinking water processing N2 - PdSn catalysts prepared by various methods and used for nitrate reduction were investigated by means of in situ 119mSn Mössbauer spectroscopy. Characterization by 119mSn Mössbauer spectroscopy revealed significant differences concerning the modification of the palladium particles supported on alumina. The controlled surface reaction preparation method (CSR) leads to formation of PdSn alloys with different tin contents besides small amounts of Sn(II) species and unalloyed metallic Sn. On the other hand the impregnation method leads to a small amount of PdSn alloys and higher contents of Sn(II) species. Sn(IV) species were found in both kinds of catalysts. The CSR prepared PdSn catalysts showed an improved activity and selectivity compared to the catalysts obtained by the impregnation method. PY - 2000 DO - https://doi.org/10.1023/A:1012688627310 SN - 0304-3843 SN - 1572-9540 VL - 126 IS - 126 SP - 89 EP - 93 PB - Kluwer CY - Dordrecht AN - OPUS4-986 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lucka, R. A1 - Elshani, B. A1 - Kilic, M. S. A1 - Klimke, S. A1 - Krüger, C. A1 - Menzel, Michael A1 - Stößer, R. A1 - Titiš, J. A1 - Boča, R. A1 - Renz, F. T1 - ESR and Mössbauer spectroscopy of iron(III) spin crossover complexes based on pentadentate Schiff base ligands with pseudohalide coligands N2 - Two iron(III) spin crossover complexes [Fe(5Cl-L)(NCS)] (1) and [Fe(5Cl-L)(NCSe)] (2) were synthesized with the pentadentate Schiff base ligand 5Cl-L and thiocyanato and selenocyanato as coligands. 5Cl-L, as an asymmetric {N3O2} donor Schiff base, was synthesized by a condensation reaction of 5-chlorosalicyladehyde using the asymmetric N-(2-aminoethyl)-1,3-propanediamine. The complexes exhibited a spin crossover at 280 (1) and 293 K (2), respectively, and were subjected to electron spin resonance (ESR) and Mössbauer spectroscopy at 77, 295 and 325 K. Ab initio CASSCF calculations followed by the NEVPT2 method were applied for predicting the g-tensor components as well as Mössbauer parameters. KW - Spin crossover KW - Iron(III) complexes KW - Mössbauer spectroscopy KW - ESR spectroscopy KW - Ab initio calculations PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634061 DO - https://doi.org/10.3390/magnetochemistry11050043 SN - 2312-7481 VL - 11 IS - 5 SP - 1 EP - 9 PB - MDPI CY - Basel AN - OPUS4-63406 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Renz, F. A1 - Jung, S. A1 - Klein, M. A1 - Menzel, Michael A1 - Thünemann, Andreas T1 - Molecular switching complexes with iron and tin as central atom N2 - The precursor [FeIII(L)Cl] (LH