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1.
Decomposition of KF · H2O2 stabilized with carboxylic acids (maleic, fumaric, succinic, adipic) in storage for more than three years at 20°C was studied. Rate constants of decomposition of stabilized KF · H2O2 were determined in different time intervals. The chemical reactions in the system KF-H2O2-carboxylic acid in the stage of preparation of solid KF · H2O2 stabilized with carboxylic acid and those during prolonged storage of the final product are discussed.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 2, 2005, pp. 287–291.Original Russian Text Copyright © 2005 by Titova, Nikol’skaya, Buyanov, Pudova, Karzhavina.  相似文献   

2.
Structural models for stabilized O in -irradiated alkaline ices are evaluated. INDO calculations on hydrated O indicate octahedral coordination and hydrogen bond orientations for the water molecules are preferred. INDO results for hydrated OH are compared with crystallographic data for NaOH hydrates: a scaling factor for calculated hydrogen bond lengths is developed and applied to hydrogen bonded O models. The hydrated O model is closely similar to the hydrated anions in KF · 4H2O, NaOH · 4H2O, and NaOH · 7H2O. A second model is developed, involving H3O+ along with H2O, in the O stabilization shell. Both models are discussed in terms of alkaline ice radiation chemistry.  相似文献   

3.
Potassium fluoride peroxosolvate KF-H2O2 was obtained upon action of a 30% aqueous solution of hydrogen peroxide on solid potassium fluoride dihydrate. As compared to other peroxosolvates, KF-H2O2 is characterized by the highest thermal stability: the decomposition rate constantk 1, at 120°C is 1.4 10–3 min–1, the enthalpy of H2O2 addition to KF is 8.1 kcal/ mol. The correlation between the high stability of KF-H2O2 and the absence of catalytic properties of KF towards H2O2, and the formation of strong intermolecular O-H...F and intramolecular O-H...O hydrogen bonds in the crystal is discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 38–44, January, 1993.  相似文献   

4.
A new magnesium borate Mg2[B2O4(OH)2]·H2O has been synthesized by the method of phase transformation of double salt at hydrothermal condition and characterized by XRD, IR, TG and DSC. The enthalpy of solution of Mg2[B2O4(OH)2]·H2O in 0.9764 mol L–1 HCl was determined. With the incorporation of the enthalpies of solution of H3BO3 in HCl (aq), of MgO in (HCl+H3BO3) (aq), and the standard molar enthalpies of formation of MgO(s), H3BO3(s), and H2O(l), the standard molar enthalpy of formation of –(3185.78±1.91) kJ mol–1 of Mg2[B2O4(OH)2]·H2O was obtained.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

5.
Conclusions The new molecular compound NH4F·H2O2 was observed during an investigation of the fusibility of the NH4F-H2O2-H2O system and has been isolated.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1617–1618, July, 1968.  相似文献   

6.
The novel zeolite CF-3, with a high ratio of SiO2/Al2O3 and a characteristic X-ray powder diffraction pattern, has been synthesized hydrothermally from a TMEDA-Na2O–SiO2–Al2O3–H2O system at 200°C. The molar composition of CF-3 is (0.4–0.6)Na2O·(1.5–6.3)TMEDA·Al2O3·(80–400)SiO2·(0–17)H2O·CF-3 is similar to ZSM-39 and melanophlogite, which have a clathrate-type structure.  相似文献   

7.
Conclusions HO2 radicals were detected in the partial decomposition product of K2CO3·3H2O2 by the EPR method.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1638–1639, July, 1973.  相似文献   

8.
A number of sensing systems based on indium oxide doped with various metal oxides (In2O3 · WO3, In2O3 · ZnO, In2O3 · RuO2, In2O3 · Gd2O3, and In2O3 · Sm2O3) in amounts of no more than 3–5 mol % and also Au · In2O3 films were studied as sensors for detecting NO2 in air. The working temperature of sensors was 250°C (except for In2O3 · RuO2, for which T = 150–190°C). In2O3 · WO3-based sensors reach a high sensitivity especially at a concentration of NO2 in air higher than 10 ppm (the relative sensor conductivity changes by 2.5 orders of magnitude). However, a shortcoming of this system is an increased response time (7–9 min) as compared to the other studied systems, for which the response time does not exceed 15–20 s. In2O3 · Gd2O3 and In2O3 · Sm2O3 films exhibit the best sensing properties in sensitivity, selectivity, and stability. Various NO2 species adsorbed on the surface of dispersed indium oxide were detected by Fourier-transform IR spectroscopy. The mechanism of changing the conductivity of In2O3 · Gd2O3 films upon detecting NO2 in air is discussed.  相似文献   

9.
Conclusions The heats of dissolution of hydrogen peroxide in water have been measured, and on the basis of this we have calculated the standard enthalpies of formation of KF and KF·nH2O2 (where n=1–3). We have also calculated the enthalpy of the combination of H2O2 to KFcr.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 247–250, February, 1989.  相似文献   

10.
The infrared spectra, in the 700–200 cm–1 region, have been reported for6LiHCO2 · H2O,6LiHCO2 · D2O,7LiHCO2 · H2O and7LiHCO2 · D2O and the observed fundamental bands have been discussed taking into account the6Li/7Li and H2O/D2O isotope wavenumber shifts on the fundamental vibrations.
Infrarotspektren (700–200 cm–1) und6Li/7Li- und H2O/D2O-Isotopeneffekte für vier isotopensubstituierte Lithiumformat-monohydrate
Zusammenfassung Die Infrarotspektren in der Region von 700–200 cm–1 werden für6LiHCO2 · H2O,6LiHCO2 · D2O,7LiHCO2 · H2O und7LiHCO2 · D2O angegeben und die beobachteten Grundschwingungen zusammen mit den isotopischen Verschiebungen der Wellenzahlen diskutiert.
  相似文献   

11.
The solid—liquid equilibria of the ternary system H2O—Al(NO3)3—Mg(NO3)2 were studied at –30, –20, –10 and 0°C by using a synthetic method which allows to detemine all the characteristic points of isothermal sections. The stable solid phases which appear are respectively: ice, Al(NO3)3·9H2O, Mg(NO3)2·9H2O and Mg(NO3)2·6H2O. Neither double salts nor mixed crystals are observed in the temperature and composition field studied. Polytherm diagram layout show two invariant transformations correspond with an eutectic point and a peritectic point.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

12.
It is shown by pulse radiolysis that in aqueous solutions of hydrazine containing oxygen the radical N2H3 reduces oxygen to O2 at pH > 7 (k 3·109 dm3· mole–1·sec–1), while this reaction does not occur for the protonated form N2H4 + at pH < 7 (k, 5·106 dm3·mole–1·sec–1). The rate constants for the disappearance of O2 have been determined in the pH range from 4 to 12. Rate constants have been calculated for the reaction of O with N2H4 [k=(1.6 ±0.2)·109 dm3·mole–1·sec–1] and of O3with N2H4 [k=(1.2 ±0.2)·106 dm3· mole–1·sec–1].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 341–345, February, 1991.  相似文献   

13.
By-product formation in spark breakdown of SF6/O2 mixtures   总被引:2,自引:0,他引:2  
The yields of SOF4, SO2F2, SOF2, and SO2 have been measured as a function of O2 content in SF6/O2 mixtures, following spark discharges. All experiments were made at a spark energy of 8.7 J/spark, a total pressure of 133 kPa, and for O2 additions of 0, 1, 2, 5, 10, and 20% to SF6. Even for the case of no added O2, trace amounts of O2 and H2O result in the formation of the above by-products. However, addition of O2 significantly increases the yields of SOF4 and SO2F2, while SOF2 is only slightly affected. The net yields for SOF4 and SO2F2 formation range from 0.18×10–9 and 0.64×10–10 mol·J–1, respectively, at 1% O2 content to 10.45×10–9 and 7.15×10–10 mol·J–1, respectively, at 20% O2 content. The mechanism for SOF4 production appears to involve SF4, an important initial product of SF6, as a precursor. Comparison of the SOF4 and SO2F2 yield from spark discharges (arc and corona) shows that the yields from other discharges (arc and corona) shows that the yields can vary by at least three orders of magnitude, depending on the type of discharge and on other discharge parameters.  相似文献   

14.
Experimental data on the equilibria Fe2+/Fe3+ and SO3 2−/SO4 2− in the system Fe(OH)3(H2SO4)-Na2SO3-H2O are presented. The quantitative relations between the reduction of Fe(III) and the precipitation of FeSO3·2.5H2O as a Fe2O3 precursor have considered graphically.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 1, 2005, pp. 41–44.Original Russian Text Copyright © 2005 by Vasekha, Motov.  相似文献   

15.
Studies of glasses and their crystalline products in the TeO2–V2O5 system were made in the 1400–400 cm–1 range. A continuous shift of the V=O-band from 1020 cm–1 to 940 cm–1 was found in the glasses with decreasing concentration of V2O5, as well as a sharp decrease in the intensity at 830 cm–1. On the basis of the results obtained, it is concluded that with increasing TeO2 content, the structure of the glasses is changed, caused by the breaking of the V–O–V bonds and the formation of Te–O–Te bridges.The IR-spectrum of the 2TeO2·V2O5 compound in both crystalline and vitreous states was studied for the first time. The behaviour of the absorption bands is related to the structure of the glasses studied.

Mit 4 Abbildungen  相似文献   

16.
Conclusions The solubility of rubidium and cesium sulfates in aqueous solutions of sulfuric acid was studied at 25°. Rubidium sulfate forms the compounds 3Rb2SO4· H2SO4, Rb2SO4 · H2SO4, Rb2SO4·3H2SO4 and Rb2SO4·7H2SO4 with sulfuric acid, while cesium sulfate forms the compounds Cs2SO4·H2SO4; Cs2SO4·3H2SO4 and Cs2SO4 · 7H2SO4.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1166–1170, June, 1968.  相似文献   

17.
The effects of various factors on the formation of O2 radical anions in the adsorption of an NO + O2 or NO2 + O2 mixture on ZrO2 were studied. It was found that the thermal stability of the O2 species depends on the composition of the adsorbed gas. It was suggested that nitrogen oxide complexes on ZrO2 centers are responsible for the formation of O2 . These centers are formed upon the treatment of the oxide in a vacuum; however, they are different from both coordinatively unsaturated Zr4+ cations (NO adsorption centers at 77 K) and Zr4+–O–O–Zr4+ centers, at which O2 are formed because of the adsorption of H2 + O2. Based on the experimental data, the mechanism of O2 formation in the adsorption of an NO + O2 mixture is discussed.  相似文献   

18.
Conclusions The compounds RbF · H2O2, RbF · 2H2O2, and CsF · H2O2 have been synthesized for the first time, and their thermal stabilities were investigated.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1871–1873, August, 1972.  相似文献   

19.
The energy surface of the dihydrated fluoride anion (F·2H2O)–1 is studied for a number of different geometry points near the equilibrium structure within the SCF LCAO MO framework, using an extended gaussian basis set to approximate the molecular wavefunctions. For the first and second hydration step of the fluoride anion the corresponding hydration energies are calculated to beB 1 scf =24.1 kcal/mole andB 2 SCF =20.8 kcal/mole (experimental measurements: 23.3 kcal/mole and 16.6 kcal/mole, respectively). The hydration energies and equilibrium bond distances obtained for the dihydrated fluoride anion (F·2H2O) are compared with those found for the monohydrate (FHOH) and with corresponding results of the dihydrated lithium cation (Li · 2H2O)+. The system (F·2H2O) is taken as a very simple model to discuss some basic features of the hydration process of small ions and to study the influence of a negative ion on an adjacent hydrogen bond.We would like to thank our technical staff for valuable help in carrying out these calculations.  相似文献   

20.
Blue-coloured gels have been prepared in the VO2-SiO2 system up to 80 mol% VO2 by sol-gel technology using TEOS and aqueous solutions of VOSO4·5H2O. It is established by means of VIS and ESR spectra that at low temperatures VO2+ complexes are formed. An oxidation of V4+ has taken place with increasing temperature, and V2O5 and cristobalite have been separated. Silica gel glasses stable up to 800°C have been obtained from gels containing 1–3 mol% VO2.  相似文献   

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