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The technique of X-ray photoelectron spectroscopy has been used to investigate the chemical reactivity at the metal/CuO interfaces. Thin films of the metallic overlayer (0.5 nm, 1.0 nm and 2.0 nm thickness) were deposited on copper oxide substrates at room temperature. In situ characterization of the interfaces has been performed. The 2p core level regions of the metals have been investigated. The spectral features show considerable reactivity at the interfaces. The core level peaks of the metal are observed to be shifted to the high BE energy side with the appearance of satellites. The spectral data confirm the formation of the metallic oxide at the interface. The satellite structure in the copper region is observed to disappear and the spectral features are found to approach those of elemental copper. The room temperature deposition of the metal on copper oxide therefore results in the reduction of copper oxide to elemental copper followed by the oxidation of the metal. The interface is found to consist of a mixture of metal oxide and elemental copper. The 2.0 nm samples were annealed. These samples show the diffusion of copper oxide through the overlayer. The metal reacts with this diffusing oxide to form metallic oxide. The interface is found to consist of a mixture of unreacted metal, the metal oxide, and elemental copper. The amount of the unreacted metal varied between 0% and 40% and can be controlled by the processing conditions. The investigation shows room temperature chemical reactivity at the metal/CuO interface and provides a new method of preparing sub-nano-oxide films.

Currently, electrochemical anodizing is one of the most common processes in materials science, since, under the right conditions, it allows to modify the material surface without damaging it by means of redox reactions, generating an oxide layer that protects the material and improves its properties. In this paper, grade 2 titanium was anodized using a solution of hydrochloric acid, glycerol, and deionized water as electrolyte, and 0.5 M K₂CrO₄ as doping agent, with a voltage of 30 V for 4.5 h. After anodizing with and without chromium, annealing was performed at different temperatures (500${}^{\circ }$C, 600${}^{\circ }$C and 700${}^{\circ }$C) to promote structural and microhardness changes. The samples were analyzed by FE-SEM observing that the formation of nanostructures changes according to the heat treatment, where samples at 700${}^{\circ }$C with chromium begin to form nanorods and, compared to those without chromium, the nanorods are longer. The presence of Cr in anodized TiO₂ at different temperatures was confirmed by EDS technique. Using XRD, the microstructure of TiO₂ anodized with and without Cr was analyzed and anatase and rutile phases were found, with greater presence of anatase for samples with Cr. Finally, a maximum hardness of up to 10.27 GPa was obtained from the sample at 700${}^{\circ }$C without chromium, which is higher compared to the values of coatings with Cr. However, the anatase phase could be stabilized at higher temperatures making it suitable for medical applications since the anatase phase is the most biocompatible.

Using a Morse type pair potential, molecular-dynamics simulations have been performed to investigate the atomic geometries, growing patterns, structural stabilities, energetics and magic sizes of Ti_n, V_n and Cr_n (n = 2-50) clusters. Following rearrangement collision of the atom–cluster system in fusion process, and absorbing their energies step by step down to 0 K, possible optimal equilibrium geometries of the clusters have been generated to tackle the structural determination problem. This approach serves an efficient alternative to the growing path identification and the optimization techniques. It has been found that titanium, vanadium and chromium clusters prefer to form three-dimensional compact structures in the determined configurations and the appearances of medium sizes are, in general, five-fold symmetry on the spherical clusters. Moreover, relevant relations between atomic arrangements in the clusters and the magic sizes have been observed.

A metal complex of general formula Cr(II)-C₂₆H₁₄N₈ has been obtained as an amorphous compound and studied by means of IR and Energy Dispersive X-ray Diffraction (EDXD). The chemical composition and the IR signals of the sample suggest that the hemiporphyrazine is bound to the metal atom via nitrogen atoms. EDXD data confirm this finding and show that the compound structure is composed of two parallel stacks of seven planar macro-molecules. The second stack is rotated by 5° around the z axis originating in its center of mass and the molecules are lying on parallel planes to xy plane.

The Soret maxima of a number of metallotriarylcorroles shift sensitively in response to varying substituents on the meso-aryl groups. The effect is most pronounced for copper corroles but is not seen for silver and gold corroles. In the copper case, the effect has been attributed to a small HOMO–LUMO gap. Chromium-oxo corroles share a small HOMO–LUMO gap with copper corroles, as well as a substantially metal-based LUMO, yet the Soret maxima of chromium-oxo triarylcorroles do not shift in response to substitution on the meso-aryl groups. Molybdenum-oxo corroles are substituent-insensitive in the same sense. TDDFT calculations, focusing on chromium-oxo and molybednum-oxo triarylcorroles, are reported here in an attempt to explain the divergent spectroscopic behavior of different metallocorrole families.

The reaction of axial coordination of imidazole derivatives by (X)CrTPP in amphiprotic media was studied. The reaction includes two stages: consecutive substitution of the two alcohols molecules, first in the outer coordination sphere, and then in the inner sphere. For the reaction of the intrasphere substitution the solvolytic associative-dissociative mechanism has been found. The molecule of (chloro)chromium(III) porphyrin and its derivatives have been studied by density functional theory (DFT) computations utilizing the B3LYP hybrid method.

Chromyl(V) complexes of eleven different meso-aryl- and $\beta$-alkylcorrole ligands have been prepared and characterized by analytical, spectroscopical, electrochemical and structural means. All seven new complexes show the expected optical spectra of chromyl(V) corroles with the Soret band situated slightly above (meso-arylcorroles) or below ($\beta$-alkylcorrole) 400 nm, and with an isotropic room temperature EPR signal for the $d^1$ ion Cr(V) at about $g_{\mathrm{\text{iso}}}=1.985$. Cyclic voltammetry evidences two or three quasi-reversible one-electron redox steps, which are characterized as two ligand-centered processes and one metal-centered process based on spectroelectrochemical measurements and a Hammett analysis. Chemical reduction to a chromyl(IV) corrolate was successfully performed using NaHg and NEt₃. Citric acid, however, produces a different reduction product, for which an isocorrole structure is proposed. Six chromyl(V) corroles could be analysed by seven single crystal diffraction analyses. The obtained molecular data prove the presence of remarkably similar CrN₄O coordination units independent of the corrole substitution pattern, and of macrocyclic conformations which can be understood as comprised mainly of a doming mode, a more or less pronounced saddling mode, and one out of two different and dominating ruffling modes.

The multi-cations doped LiVPO₄F, nominally Li_0.97Cr_0.01V_0.95Al_0.01Nb_0.02PO₄F_0.97, is prepared by Chromium (Cr) doping on lithium site and Al–Nb co-doping on vanadium site via a conventional carbothermal reduction (CTR) route. The crystallographic lattice volume, particle size and morphology are not obviously changed comparing with un-doped LiVPO₄F. However, the high rate and lifetime cycling performances are noticeably improved although the capacities at very low currents are slightly decreased. The reversible capacity at 1/10 C, 1 C, 2 C and 4 C of the pristine LiVPO₄F is 143 mA h g^-1, 99 mA h g^-1, 86 mA h g^-1 and 70 mA h g^-1, respectively, while that of the doped counterpart is 138 mA h g^-1, 102 mA h g^-1, 95 mA h g^-1 and 82 mA h g^-1, respectively. The capacity retention after 100 galvanostatic cycles at 1.5 C is enhanced from 85.4% to 90.9% by such multi-cations doping. Moreover, the initial coulombic efficiency is significantly increased from 81.8% to 90.3% as well.

Ferromagnetism in non-metallic solids is quite a rare property. In solids containing molecular building blocks it is even rarer. One strategy for preparing ionic ferromagnets is to combine a low-dimensional continuous lattice containing transition-metal ions with organic molecular ions. In this article we review the synthesis, structures and magnetic and optical properties of halogenochromate(II) salts with substituted ammonium cations. The shape of the latter has a striking influence on the bulk magnetic behaviour of the solids. Monosubstituted cations yield tetrahalogenochromates(II) with layer structures which are ferromagnets with Curie temperatures up to 60 K. On the other hand, tetramethylammonium trihalogenochromates(II) are one-dimensional antiferromag-nets. The striking difference in the intensities of the visible absorption spectra of the two classes of materials can be explained by an exchange-induced electric-dipole mechanism.

In comparison to the Cr-added hot-dip galvannealed DP steel with fully-recrystallized and equiaxed grains, the Mo-added hot-dip galvannealed DP steel shows small quasi-polygonal grains. The Mo-added hot-dip galvannealed DP steel shows better mechanical properties than Cr-added hot-dip galvannealed DP steel. The increased yield and tensile strengths in the Mo-added steel hot-dip galvannealed DP are mainly caused by grain refinement and martensite transformation. It is recognized that Cr and Mo suppress cementite transformation in the steels, but Cr is not as strong as that of Mo. Compared with Cr-steel, discontinuous yielding in the stress-strain curve did not appear in the Mo-steel because the martensite volume fraction was greater than the 5%.

The removal of chromium (VI) from water with used cigarette filters was studied by batch contact experiments. The effects of contact time, pH, dosage of the filters, and temperature on the yield of Cr(VI) removal were investigated. The results show that the reaction of Cr(VI) and the filters reaches equilibrium in 2 h, and pH value has a significant role on the reaction. The efficacy of Cr(VI) removal rises with decreasing pH as well as with an increasing amount of filters, but changes little with temperature between 30 and 50 °C. Experiments at 30 °C, a pH of 1, with a 250:1 solution to filters ratio, and simulation with a Langmuir model indicate that one kilogram of filters remove 9.5 grams of Cr(VI) at most.