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BaFeO2.8−δwith a crystal structure different from any of those previously reported in the system BaFeOy(2.5≤y≤3.0) was prepared by a low-temperature method of synthesis, based on the oxidative thermal decomposition of BaFe[(CN)5NO]·3H2O. The structure was solved ab initio by high-resolution synchrotron X-ray powder diffraction and refined by Rietveld analysis (RP=7.78, Rwp=11.3, Rexp=3.76, RBragg=6.67, χ2=9.03). The compound crystallizes in the hexagonal crystal system, space group P63/mmc, Z=10, unit cell parameters a=5.77944(1), c=24.60871(6) Å. The structure consists of 10H close packed (hchch)2stacking of BaOnlayers (eight BaO3layers and two oxygen-deficient BaO2layers). Additional oxygen deficiencies are randomly distributed on the hBaO3layers. Six iron ions occupy octahedral sites sharing faces between them along the caxis and four occupy tetrahedral sites (2 T+and 2 T−) sharing faces with the octahedra and sharing corners between them.

The distribution of alkali metal picrates in the mutually saturated water–dichloromethane solvent system at 298.15 K was investigated. From distribution data, the partition and the distribution constants of these salts in this solvent system and the ion-pair formation constants of alkali metal picrates in water saturated dichloromethane were calculated. For salts containing the smaller alkali metal cations, significant differences were found between the partition and the transfer Gibbs energies in this solvent system. The former data are referred to the mutually saturated solvents whereas the latter involve water and dichloromethane in their pure state. In order to (i) formulate an equation which is representative of the extraction process taking place when an aqueous solution containing the free metal ion salt is equilibrated with a solution of calixarene ester in dichloromethane and (ii) gain information regarding the behaviour of calixarene ester salts in non-aqueousmedia, conductance measurements were performed in acetonitrile and pure and wet dichloromethane at 298.15 K.Whenever possible, the ion-pair formation constants and the limiting molar conductances were calculated from the analysis of data using a well established treatment. The results obtained are discussed. From distribution experiments in the presence of ethyl p-tert-butylcalix[4]arene tetraethanoate in the mutually saturated solvents, the distribution and extraction constants for alkali metal picrates were calculated. Good agreement was found between the distribution constants derived from data in the absence and presence of the ligand. The individual processes involved in the overall extraction of cations by ethyl p-tert-butylcalix[4]arene tetraethanoate were assessed. The results were compared with corresponding data for the mutually saturated water–benzonitrile solvent system. It is concluded that the higher extraction constants obtained in the latter solvent system are mainly attributed to the more favourable distribution constants in water–benzonitrile relative to water–dichloromethane. Based on the experimental evidence shown in this paper, some of the statements made in the literature regarding these systems are discussed. The effect of the solvent on the selective extraction of alkali metal cations from water is discussed.

The low-temperature formation of Sr and Ca ferrates by thermal oxidative decomposition of tetrahydrates of Sr and Ca nitroprussides (pentacyanonitrosilferrates(II)) is reported. IR spectroscopy, X-ray diffraction (including Rietveld analysis), and thermal analysis were used to follow the process. The amount of active oxygen (concentration of Fe(IV)) in the products was chemically determined. For the Sr compound, the final product was an oxygen-deficient perovskite that could be produced with a very low content of carbonate in the temperature range 750–850°C. For the calcium compound, only Ca2Fe2O5with the brownmillerite type structure was obtained.

The title compound, Rb2[Fe(CN)5NO], crystallizes in the space group P212121, witha=5.687(1),b=15.956(2),c=12.645(3) Å, andZ=4. Anions are in equivalent C1 sites (one per asymmetric unit) and are slightly distorted octahedra (C4v ideal symmetry). TGA and DTA curves and vibrational (infrared and Raman) spectra of Rb2[Fe(CN)5NO] were obtained. Results are interpreted in view of the crystal structure of the compound and the behavior of related substances.

The infrared absorption bands due to the water molecules in calcium nitroprusside monohydrate and tetrahydrate were studied using partial deuteration and low-temperature techniques. An assignment of these bands based on the possible hydrogen bonds existing in the crystal lattice is proposed. Additional infrared spectroscopic data on the monohydrate and the anhydrous compound are included.

Infrared spectra of potassium azidopentacyanocobaltate(III) dihydrate (PACDH) were obtained from the polycrystalline substance, both normal and deuterated, and from the monocrystal using in this case a polarization analyzer. Raman spectra of the normal powder were also obtained. The observed bands were assigned either to the internal vibrational modes of the azidopentacyanocobaltate(III) ion (AC) or to the internal and librational modes of the hydration water.

The infrared and laser-Raman spectra of Sr2V2O7 are reported and discussed by means of a “Site Symmetry” analysis. The principal force constants as well as the mean amplitudes of vibration for the V2O74- ion have been calculated using a simplified molecular model. Some aspects of the vibrational behaviour of the V-O-V bridge in this ion are also discussed.

The thermal behaviour of Na5[Fe(CN)5SO3]·2H2O has been investigated by thermogravimetric and differential thermal analysis. Detailed studies of the decomposition residues using various physicochemical methods show that decomposition occurs in a manner similar to that previously postulated for related compounds.

The results of a DTA study between room temperature and 90 K on barium nitroprusside trihydrate, (BaNP), Ba[Fe(CN)5NO]·3H2O, complemented by temperature-scanning IR transmission spectroscopy are reported.

The infrared spectra of polycrystalline K3[Mn(CN)5NO]·2H2O at different degrees of deuteration were recorded between 4000 and 200 cm-1, both at room and low temperature. The room-temperature Raman spectrum of the isotopically normal powder was also obtained. The observed bands were assigned to the internal vibrational modes of the [Mn(CN)5NO]-3 ion and to the internal and librational modes of water of hydration. In accordance with X-ray diffraction studies, the spectra showed the existence of two crystallographically distinct types of water molecules located in different sets of sites ofC1 symmetry.

The crystal structure of the title compound has been determined from diffractometer data and refined with isotropic thermal parameters to finalRw factors ofR=0.058 andRw=0.056. It crystallizes in the orthorhombic space groupp212121 (No. 19), witha=9.706(7),b=18.826(6), andc=25.258(6) Å. The asymmetric unit contains four nitroprusside ions, eight potassium ions, and five water molecules, one of which shows disorder. The infrared spectra of the polycrystalline compound, both normal and with different degrees of deuteration at temperatures ranging from liquid nitrogen to room temperature, were obtained. The vibrational spectra present an unusual number of fundamental and first overtone NO stretching bands and a rich structure in the water bending region, in accordance with the existence of inequivalent nitroprusside ions and water molecules.

The crystal and molecular structure of the title compound has been determined by X-ray diffraction methods. It crystallizes in the monoclinic space groupP21/n witha=10.072(2),b=19.434(7),c=19.462(3) Å,ß=101.07(1)° andZ=4. The anion has a geometry similar to that observed in other related complexes. The two water molecules are hydrogen bonded to each other and are located at van der Waals distances from nitrogen atoms of neighbor nitroprusside anions.

Die Elektronenspektren des OsO3N⊖-Ions in Wasser und flüssigem Ammoniak werden gemessen und diskutiert. Das Spektrum in flüssigem Ammoniak weist eine deutlich ausgeprägte Schwingungsfeinstruktur auf. Das Verhalten des Ions in wäßriger Lösung wird untersucht und die Äquivalentleitfähigkeit bei unendlicher Verdünnung gemessen. Weiterhin erfolgt eine Diskussion der Schwingungseigenschaften und Bindungsverhältnisse.

Die Valenzschwingungen zahlreicher Ag- und Tl-Salze von Oxoanionen sind gegenüber anderen Salzen stark nach kleineren Wellenzahlen verschoben. Entsprechendes gilt auch für Thio- und Nitridoanionen. Dieser Befund läßt sich durch die Ausbildung von schwachen kovalenten Bindungen zwischen Ag bzw. Tl und den Anionen deuten, da dies zur Schwächung der α-Bindungen im Anion führt.

Es wird die Herstellung der Verbindungen Sr2(MnO4)OH und Sr2(MnO4)OH·2H2O beschrieben. Die Gitterkonstanten wurden aus den entsprechenden Pulverdiagrammen berechnet. Die Infrarotabsorptions-und die Reflexionsspektren im Sichtbaren sowie das magnetische und thermische Verhalten wurden untersucht und kurz besprochen.