Mössbauer study of some novel iron-bis-glyoxime and iron-tris-glyoxime complexes

Dioximes as ligands are used as analytical reagents and serve as models for biological systems as well as catalysts in chemical processes. A number of novel mixed complexes of the type [Fe(DioxH)2(amine)2] have been prepared and characterised by FTIR, 57Fe Mössbauer and mass spectroscopy by us. We have found strong Fe–N donor acceptor interactions and iron occurred in low-spin FeII state in all complexes. Later, we have also found that the incorporation of branching alkyl chains (isopropyl) in the complexes alters the Fe–N bond length and results in high-spin iron(II) state [1, 2]. The question arises: can the spin state of iron be manipulated generally by replacing the short alkyl chains with high volume demand ones in Fe-azomethine-amine complexes? To answer the question we have synthetized novel iron-bis-glioxime and iron-tris-gloxime complexes when long chain alkyl or aromatic ligands replaced the short alkyl ones and studied by 57Fe Mössbauer spectroscopy, MS, FTIR, UV-VIS, TG-DTA-DTG and XRD methods. Novel iron-bis-glyoxime and iron-tris-glyoxime type complexes, [Fe(Diethyl-Diox)3(BOH)2], [Fe(Diethyl-Diox)3(BOEt)2] and [Fe(phenyl-Me-Diox)3(BOEt)2], were synthesized similarly as described in [2]. The FTIR, UV-VIS, TG-DTA-DTG and MS measurements indicated that the expected novel complexes could be successfully synthesized.

Magnetic, structural and Mössbauer study of soils from an ancient mining area in Huancavelica-Peru

We present the magnetic, structural and 57Fe Mossbauer characterization of soils collected from an ancient mercury contaminated city named Huancavelica in Peru. The characterization results indicate that silicates and carbonates are the main mineralogical constituents in the samples. In addition, 57Fe Mössbauer spectra at room temperature reveal, the presence of two components: a magnetic component related to magnetic Fe-oxides (magnetite, hematite, goethite) and a high non-magnetic component related to Fe+3 in high spin configuration and tetrahedral coordination in silicates. The magnetization measurements present screening of paramagnetic, ferromagnetic and antiferromagnetic signals, typical from soils containing different silicates and iron minerals. Remarkably the Verwey and Morin transitions corresponding to magnetite and hematite, respectively, are screened by the paramagnetic signal corresponding to the major silicate components in the samples. Overall, the soils are mainly composed of crystalline and amorphous silicates, calcites and iron bearing which are typical from Andean soils.

Characterization of steel billet scales generated during the continuous casting process in SIDERPERU steel plant

Tons of waste is produced during iron steel’s industrial production, creating environmental pollution. This work aims to characterize the steel scale formed on the billet surface during the last step of steel production in the SIDERPERU steel plant. Scanning Electron Microscopy (SEM) shows stacked layers one above the other on steel billets scales surface. Energy Dispersive X-ray (EDX) and X-ray Fluorescence (XRF) reveal the high content of Fe and O, with Ca, Si, Mn, and Cr as minority elemental compounds. X-ray Diffraction (XRD) shows FeO, α-Fe2O3 and Fe3O4 as crystallographic phases. Magnetometry reveals Verwey transition and paramagnetic signals that screen the Morin transition. Mössbauer Spectroscopy at room temperature displays magnetic and non-magnetic parts. The non-magnetic part has the hyperfine parameters corresponding to predominant nonstoichiometric wustite. Octahedral (Fe+2/Fe3+) and tetrahedral Fe+3 hyperfine fields of 46.0 and 49.4 T values respectively are associated to nonstoichiometric magnetite and another sextet with a hyperfine field of 52.0 T is related to hematite.

4M method – new application of Mössbauer spectroscopy to classification of meteorites. How it works?

Abstract4M method is a new application of Mössbauer spectroscopy to quantitative classification of ordinary chondrites. 4M derives from four words: meteorites, Mössbauer spectroscopy, multidimensional discriminant analysis, Mahalanobis distance. This method was published by us in 2019. In this paper we present application of 4M method to classification of four meteorites. Link to script with calculation needed for classification of ordinary chondrites was given.