[en] Ferric ferrocyanides synthesized from different sources of ferric cations and ferrocyanide anions and those derived from ferrous ferricyanide, ferrous ferrocyanide and ferric ferricyanide have been studied using Moessbauer and XRD techniques. Structural information of the effect of the provenance on the properties of the final compound is obtained. Significant correlations between isomer shift and quadrupole splitting of inner and outer iron cations have been observed. (orig.)

[en] The Moessbauer spectra of 29 nitroprussides have been measured and the parameters δ and Δ correlated with the polarizing power Z/r² of the outer cations. There is no overall correlation but there are limited groups in which a trend can be ascertained. In isoelectronic sequences such as Li⁺, Be²⁺, Mn²⁺, Fe³⁺, where the outer electronic shell remains fixed, while Z/r² increases, a definite trend of decreasing δ and Δ with increasing Z/r² is observed. (author) 5 refs.; 3 figs.; 2 tabs

[en] The interaction of ozone with Prussian Blue has been studied by Moessbauer, infrared and XRD techniques. All spectral results reveal a reversible conversion of ferrocyanide to ferricyanide with preservation of the crystal skeleton. Ferric ferricyanide obtained by ozonization of ferric ferrocyanide has Moessbauer parameters different to those of an ordered Prussian Brown, which has been attributed to secondary reaction products located at the zeolite voids of the former compound. (orig.)

No abstract available

[en] In the present work, an X-ray diffraction (XRD) and thermal study of calcium undecanoate is presented. The measured high-resolution XRD powder pattern of the synthesized salt at room temperature, using synchrotron radiation, showed that the salt is a mixture of monohydrated and anhydrous calcium undecanoate. Calcium undecanoate monohydrate proved to have a monoclinic cell with a symmetry described by the P2 1/a space group. The structure dehydrates at about 100 deg. C. After dehydration, the salt undergoes a phase transformation which results in a thermotropic mesophase. Further heating of the salt leads to decomposition and melting. Ketones are the probable products of decomposition at 400 deg. C

[en] Moessbauer spectra were recorded on hydrated, dehydrated and rehydrated hexacyanoferrate (II and III) samples including alkaline, alkaline-earth, transition metal and rare-earth salts. The location of the water molecules around the complex hexacyanoferrate anion has a decisive role on the quadrupole splitting of the low-spin Fe^III cation. (orig.)

[en] Novel mixed valence states have been obtained by the treatment of cobaltous ferrocyanides (Co⁺²Fe^II) and ferricyanides (Co⁺²Fe^III) in an ozone flow. The CN stretching bands occur at 2085 cm^-1 for Co⁺²Fe^II and at 2160 cm^-1 for Co⁺²Fe^III. After the ozonization process of Co⁺²Fe^II, an intense band approximately at 2125 cm^-1 is detected. This intermediate band must correspond to a mixed valence state of the type: Fe^II-CN-Co²⁺-NC-Fe^III Moessbauer spectra recorded 'in situ' during the ozonization of Co⁺²Fe^II show the presence of two components: A doublet with isomer shift and quadrupole splitting values close to the cobalti ferricyanide and a very broad line for the mixed valence state. From the Moessbauer and infrared spectra of the aged samples of the Co⁺²Fe^II after ozonization, a relaxation process to the initial state of the samples is observed but the mixed valence state is stable. (orig.)

[en] Highlights: • XPS as structural sensor in nd¹⁰ metal cyanides. • Effect of the local disorder in metal cyanides on their XPS spectra. • Extracting structural information from XPS spectra. • Metal-metal bonding in AuCN as detected by the XPS spectrum. • Combined Raman and XPS spectroscopies in the study of nd¹⁰ metal cyanides. -- Abstract: nd¹⁰ metal cyanides have an interesting coordination chemistry where the properties of the involved metal and the cyanide ligand are combined to form coordination polymers with attractive physical properties. X-ray photoelectron spectroscopy (XPS) has proven to be an appropriate technique to provide information on the coordination chemistry of transition metal cyanides, including coordination geometry for the involved metal, coordination mode of the CN ligand, and electron density redistribution due to the well-known π-back bonding effect in transition metal cyanides, etc. This contribution discusses on the structural information contained in the XPS spectra of nd¹⁰ metal cyanides, CuCN, AgCN, AuCN, Zn(CN)₂, Cd(CN)₂ and Hg(CN)₂. The results from XPS data were complemented with the corresponding Raman spectra. To the best of our knowledge, this is the first systematic study of this metal cyanides series from XPS data and considering the available structural information for each of the series members. The results herein discussed are relevant because this series of metal cyanides finds important industrial applications and have relevant functional properties. Of these six nd¹⁰ metal cyanides, only for copper the NIST XPS Data Base has available information.

[en] Raney type catalysts were prepared by means of a two step procedure: (1) Mechanical alloying of the metal and, (2) alkaline aluminum leaching. Mechanical alloying is a novel alternative related to the synthesis of skeletal Ni catalysts. X-ray diffraction, and Moessbauer spectroscopies were performed for catalysts characterization. Binary Al-Ni and ternary Al-Ni-Fe alloys were produced by mechanical alloying from pure metallic powders; in particular, the intermetallic β-(AlNi) phase was formed with a fine microstructure as a non-equilibrium phase; then, aluminum was selectively removed. After aluminum leaching the β-(AlNi) phase was transformed into the more stable nickel fcc structure. (author)

No abstract available