Z. K. Nikitina

Mass-spectrometric investigation of electron-impact-induced ionization of chlorine dioxide and chloryl fluoride molecules

Conclusions1.Using the electron-impact method the authors have investigated the ionization of ClO2 and ClO2F molecules with formation of positive and negative ions.2.They have calculated the energies of the F-ClO2, O, F-ClO, and O-C1OF bonds, the heats of formation of ClO2F and ClOF, and the lower limits of the electron affinity of ClO, ClO2, and ClOF molecules.

Enthalpy of formation of anhydrous aluminum perchlorate

1. The standard enthalpy for the formation of anhydrous aluminum perchlorate was determined (−136.5 +-0.5 kcal/M). 2. From a calculation of the lattice energy it follows that the bond in the unsolvated aluminum perchlorate has a partially covalent character.

Thermochemical properties of anhydrous and hydrated alkaline-earth metal and magnesium perchlorates

A low-temperature method of obtaining anhydrous magnesium, calcium, strontium, and barium perchlorates and their hydrates was developed. Hexa-Mg(ClO4)2, Sr· (ClO4)2·H2O, and Ba(ClO4)2·H2O were prepared for the first time. The enthalpies of dissolution of anhydrous magnesium and strontium perchlorates and Mg, Ca, Sr, and Ba perchlorate hydrates in water were measured; the standard enthalpies of their formation were determined. The enthalpies of dehydration of M(ClO4)2· nH2O in stages were determined.

Synthesis of perchloratocobaltates (II) of cesium, rubidium, and ammonium

1. The authors have investigated the reaction of cobalt(II) chloride and its complex chlorides with anhydrous perchloric acid and with solutions of ionic perchlorates in perchloric acid. The rate of replacement of chloride by perchlorate in the coordination sphere of cobalt depends on the composition of the initial chloride, the extrasphere cation, and the presence of ClO 4 − ions in the solution. 2. They have developed the synthesis conditions for three new cobalt complexes of the composition MCo(ClO4)3 (M is Cs, Rb, or NH4) with bidentate perchlorato groups, and have isolated and characterized them.

Perchloric acid in the synthesis of covalent perchlorates

1. The authors have investigated the conditions of hydration of multivalent metal ions by perchloric acid; hydration does not occur in acid containing oxonium perchlorate. Transfer of water from perchloric acid to the ion being hydrated proceeds via a stage of formation of oxonium perchlorate by equilibrial auto-dehydration. 2. A procedure has been developed for obtaining anhydrous perchlorates and perchlorato complexes in liquid perchloric acid.

The reaction of chlorine hexaoxide with aluminum chloride

1. The reaction of chlorine hexaoxide without a solvent, as well as in SO2 and ClO2 medium, was investigated. 2. The basic product of the reaction of Cl2O6 with AlCl3 in ClO2 medium is a crystalline complex with composition Al(ClO4)3·Cl2O6. The vibrational spectra of the complex do not contradict a partially ionic model ClO2+[Al(ClO4)4]−. 3. In the thermal decomposition of Al(ClO4)3·Cl2O6 under vacuum at 80–100°, aluminum perchlorate is obtained.

Thermochemical properties of cadmium perchlorate and its hydrates

Conclusions1.The enthalpies of solution in water at 25°C have been measured and the standard enthalpies of formation determined for (in kJ/mole): Cd(ClO4) ΔHsoln=-114.0 ±0.7, ΔHf298° =-219.7 + 1.2, Cd(C104)2·2H2O ΔHsoln=-57.84 ±0.5, ΔHf298°=-847.5 ±1.2.2.The enthalpies have been calculated for the successive hydration of cadmium perchlorate up to the dihydrate and the hexahydrate.

PMR study of the kinetics of disproportionation of anhydrous perchloric acid in a strong magnetic field

Conclusions1.The kinetics were investigated and the activation parameters of the transformation of nonequilibrium anhydrous perchloric acid into the equilibrium system 3HClO4⇄Cl2O7+H3O++ ClO4−, which takes place according to the first order, were determined.2.A mechanism of the process of disproportionation of HClO4 was proposed based on the concepts of self-association and solvation in liquid anhydrous perchloric acid.

Solvation, solvolysis, and complexing of anhydrous aluminum perchlorate in anhydrous media

Summary1.The authors have investigated the reaction between anhydrous Al(ClO4)3 and a number of organic and inorganic solvents. Aluminum perchlorate Al(ClO4)3 dissolves in CH3COOH, (CH3CO)2O, CH3OH, and C2H5OH with complete replacement of the perchlorato groups in the inner coordination sphere of aluminum by molecules of the solvent. In NOCl and N2O4, Al(ClO4)3 undergoes solvolysis to nitrosyl perchlorate and chlorido and nitrato complexes of aluminum. In solvents of medium donor strength — CH3CN, C4H8O, and CH3NO2 — the coordination of the ClO4− ions to aluminum is retained, but the mode of coordination changes from bidentate to monodentate.2.They have developed a method for obtaining Al(ClO4)3·3H2O, and it has been shown that in the latter all three perchlorato groups are monodentate.3.They have obtained for the first time tetraperchloratoaluminates and pentaperchloratoaluminate of tetrabutylammonium and have shown that they are soluble in CHCl3 and CH2Cl2.

Vibrational spectra and certain properties of anhydrous aluminum perchlorate

1. Anhydrous aluminum perchlorate is a crystalline substance with a hexagonal lattice. According to the data of the vibrational spectra, Al(ClO4)3 belongs to the class of covalent perchlorates with bidentate ClO4 groups. 2. Aluminum perchlorate, without melting, decomposes in the interval 150–450° to A12O3, Cl2, and O2, with intermediate formation of oxyperchlorates Al2O(ClO4)4 and AlOClO4.