Synthesis of pyroperoxoniobates of the alkali metals

Conclusions A new method for obtaining pyroperoxoniobates of the alkali metalswith the composition(Na, K)₄Nb₂O₁₁ · 2H₂O has been developed.The solid salts (Na, K)₄Nb₂O₁₁ · 2H₂O are stable above 100°. They decompose completely 300° with the formation of pyro salts having the composition (Na, K)₄Nb₂O₇ of reagent purity.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1281–1283, July, 1966.     

The first reported syntheses and characterisation of alkali metal trifluoronickelate(II) monohydrates,MNiF3 · H2O (M = NH4, Na or K)

Summary Ni(acac)₂ · (H₂O)₂ (1 mol) and alkali metal fluorides (4 mols), MF (M=NH₄, Na or K), react with an excess of 40% HF on a steam-bath. The product upon treatment with water gives light green crystalline alkali metal trifluoronickelate(II) monohydrate, MNiF₃ · H₂O in a high yield. Chemical analyses, pyrolysis at 120 °C, i.r. spectroscopic, and cryomagnetic (300–80 K) data have been used to characterise, and establish the identity of the compounds. While NH₄NiF₃ · H₂O behaves as a normal octahedral nickel(II) compound, NaNiF₃ · H₂O is ferromagnetic with Curie point 145 K, KNiF₃ · H₂O behaves antiferromagnetically; its Neel point is 230 K.     

Thermal decomposition of lithium peroxoborate

Conclusions In the case of the decomposition of LiBO₃·H₂O under vacuum in the interval 115–145°, 50% of the oxygen is retained in the solid phase, while 50% is liberated in the form of O₂. In this case 0.5 mole H₂O is lost. The empirical composition of the substance formed is LiBO_2.7·0.5H₂O. Complete removal of H₂O occurs at 250–300°. The activation energy of the decomposition of the peroxo-anion is 46 kcal/mole.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1218–1219, June, 1974.     

The synthesis and properties of zeolite CF-3

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.     

Water-vapor pressure and thermodynamics of the dehydration of manganese,nickel, cadmium,and lead perchlorate hydrates

The water-vapor pressure has been measured by a static method, the temperature limits for existence have been determined, and the parameters of the equation lgp [Torr]=b —a/T have been calculated for the following crystal hydrates: Mn(ClO₄)₂ · 2H₂O (90–130°C, a=3527.0,b=8.487), Ni(ClO₄)₂ · 4H₂O (60–100°C,a=3606.7,b=9.704), Ni(C1O₄)₂ · 2H₂O (110–160°C,a = 4261.7,b = 10.103), Cd(ClO₄)₂ · 6H₂O (25–58.2°C,a = 3143.7,b = 9.356), Cd(ClO₄)₂ · 2H₂O (90–144.8°C,a=3823.3,b = 9.472), Pb(ClO₄)₂ · 3H₂O (10–47°C,a = 2932.9,b = 9.391 and 47–81.5°C,a = 2448.1,b=7.877), Pb(ClO₄)₂ · H₂O (60–102.4°C,a=3610.2,b = 9.857). A hitherto unknown metastable hydrate Cd(ClO₄)₂ · 4H₂O with a phase transition at 30.9°C (20–30.9°C,a = 3669.5,b = 11.343 and 30.9–63.7°C,a=3058.6,b = 9.339) has been detected.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 466–470, March, 1993.     

Physicochemical investigation of the ternary system KF-H2O2-H2O

Conclusions An investigation of the fusibility in the system KF-H₂O₂-H₂O confirmed the existence of KF · H₂O₂ and demonstrated the formation of a new compound, KF · 2H₂O₂, which exists in the system in the interval from –70 to 20° in the region of high hydrogen peroxide concentrations.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 491–494, March, 1973.     

Thallates of alkali metals and monovalent thallium formed in aqueous solutions of their hydroxides

Conclusions As a result of an investigation of the heterogeneous equilibria in M₂O-Tl₂O₃-H₂O systems, where M=Tl(I), Li, Na, K, Rb, and Cs, at 25°C it was established that the components only react in systems with thallium(I) and sodium hydroxides with the formation of thallium(I) orthothallate and restricted solid solutions between thallium oxide and the orthothallate based on thallium oxide and sodium hydroxythallate Na₃Tl(OH)₆, respectively.At elevated temperatures of 150 and 200°C it was established that potassium metathallate is formed in the K₂O-Tl₂O₃-H₂O system while sodium metathallate NaTlO₂ and a hydrated thallate of the composition 4Na₂O·Tl₂O₃·(3–4)H₂O are formed in the Na₂O-Tl₂O₃-H₂O system at 150°C. The thallates Tl₃TlO₃, Na₃Tl(OH)₆, NaTlO₂, and KTlO₂ have been isolated in a pure form and identified.The amphoteric nature of thallium oxide has been proven.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1689–1693, August, 1984.     

Thermal reactivity of sodium manganese decavanadates

The hydrates of sodium manganese decavanadates are thermally unstable: Na₄MnV₁₀O₂₈ ·19H₂O decomposes on dehydration to give Mn(VO₃)₂, NaVO₃ and NaV₃O₈, while Na₂Mn₂V₁₀O₂₈ · 20H₂O decomposes to Mn(VO₃)₂, NaVO₃, NaV₃O₈ and NaV₆O₁₅. At a lowern(Na) n(V) molar ratio in the starting compound, a product containing a bronze with a higher vanadium(IV) content is formed. The mixtures of products are stable in the temperature ranges 500–1000°C, and 610–1000°C, respectively.

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Zusammenfassung Hydrate von Natrium-magnesiumdekavanadat sind thermisch instabil. Na₄MnV₁₀O₂₈·19H₂O zersetzt sich durch Dehydratierung in Mn(VO₃)₂, NaVO₃ und NaV₃O₈ und Na₂Mn₂V₁₀O₂₈ · 20H₂O in Mn(VO₃)₂, NaVO₃, NaV₃O₈ und NaV₆O₁₅. Bei einem niedrigerem n(Na)n(V) molarem Verhältnis der Ausgangsverbindungen wird ein Produkt geformt, welches eine Bronze mit einem höherem Vanadium(IV)-gehalt enthält. Das Produktegemisch ist im Temperaturbereich 500°–1000°C bzw. 610°–1000°C thermisch stabil.

     

Conversion of methane/carbon dioxide mixtures on vermiculite

A study has been made of the conversion of methane/carbon dioxide mixtures on a vermiculite catalyst of composition 22MgO·22SiO₂·5Al₂O₃·Fe₂O₃·4OH₂O. It has been established that at 900–970°C with molar ratios of CO₂/CH₄ of 0.5–1.5 and contact times of 10.5–21 sec the conversion proceeds quantitatively but the main products, H₂ and CO, are formed in varying proportions. An explanation has been given for the effect of the process parameters on the conversion and selectivity.Chernogolovka Institute of Chemical Physics, Russian Academy of Sciences, 142432 Chernogolovka. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1511–1515, July, 1992.     

The hydrates of sodium metasilicate peroxyhydrates

Summary A study of solubility in the system Na₂SiO₃-H₂O₂-H₂O at 0 and 15° has shown that sodium metasilicate forms a number of compounds with the general formula Na₂SiO₃· ·xH₂O₂·yH₂O, where x=2.5–3 and y=0–1.     

Preparation and Thermochemistry of Complexes of Zinc Nitrate with Threonine

The solubility property of Zn(NO₃)₂–Thr–H₂O system (Thr—threonine) at 25°C in the entire concentration range has been investigated by the phase equilibrium semimicromethod. The corresponding phase diagram and refractive index diagram were constructed. From the phase equilibrium results, the incongruently soluble compounds of Zn(Thr)(NO₃)₂ · 2H₂O, Zn(Thr)₂(NO₃)₂ · H₂O, and Zn(Thr)₃(NO₃)₂ · H₂O were synthesized and characterized by IR, XRD, TG–DTG, chemical and elemental analyses. The constant-volume combustion energies of the compounds, _c E, determined by precision rotating bomb calorimeter at 298.15 K, were –6266.88 ± 3.72, –9263.28 ± 2.23, and –11 423.11 ± 6.81 J/g, respectively. The standard enthalpies of combustion for these compounds, _c H _m ^° (complex, s., 298.15 K), were calculated as –2147.40 ± 1.28, –4120.83 ± 0.99, and –6444.68 ± 3.85 kJ/mol and the standard enthalpies of formation, _f H _m ^° (complex, s., 298.15 K), are –1632.82 ± 1.43, –1885.55 ± 1.50, and –2770.25 ± 4.21 kJ/mol. The enthalpies of dissolution of the complexes in a medium of simulated human gastric juice (37°C, pH 1, in the solution of hydrochloric acid), _dis H _m ^° (complex, s., 310 K), which were also measured by a microcalorimeter to be 13.36 ± 0.06, 15.53 ± 0.06, and 17.04 ± 0.05 kJ/mol, respectively.     

Elektrometrische Untersuchungen von Uranylarseniten

Zusammenfassung Mit Hilfe der pH- und konduktometrischen Titrationen wurde die Stöchiometrie der Verbindungen untersucht, die bei der Reaktion von Uranylnitrat mit Alkali-Ortho-, Pyro- und Metaarseniten entstehen. Der Verlauf der Titrationskurven zeigt klar die Bildung der Verbindungen 3 UO₂O · As₂O₃, 2 UO₂O · As₂O₃ und UO₂O · As₂O₃ in den pH-Bereichen 7,0–9,9 bzw. 6,0–7,5 bzw. 5,0–6,8. Der Anteil von Uranyl in den Alkaliarseniten wächst mit wachsender Konzentration von Na₂O. Die Bildung der Uranylarsenite ist also eine Funktion der H⁺-Ionenkonzentration. Wir fanden, daß die Ausfällung dieser Verbindungen fast quantitativ ist.

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The stoichiometry of the compounds formed by the interaction of uranyl nitrate and different alkali arsenites (ortho-, pyro-, and meta-) have been investigated by means of pH and conductometric titrations. The breaks and inflections in titration curves provide cogent evidence for the formation of 3 UO₂O · As₂O₃, 2 UO₂O · As₂O₃ and UO₂O · As₂O₃ in pH ranges 7.0–9.9, 6.0–7.5 and 5.0–6.8 respectively. The proportion of uranyl increases with the increase in the concentration of Na₂O molecules in alkali arsenites. The formation of uranyl arsenites is thus a function of H⁺ ion concentration. The precipitation of these compounds has been found to be almost quantitative.

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Mit 4 Abbildungen     

Benzyl cleavage in the oxidation of cycleanine by mercuric acetate

The dehydrogenation of cycleanine with mercuric acetate in 10% AcOH (at the boil) has been studied. It has been shown that it is accompanied by oxidative cleavage similar to benzyl cleavage under the action of electron impact. The main reaction product (without complexone) is the 8-(4-hydroxymethylphenoxy)-6,7-dimethoxy-2-methylisoquinolinium salt C₁₉H₂₀NO₄Cl·1.5H₂O, mp 196°C. The oxidation of cycleanine in the presence of ethylenediaminetetraacetic acid gave the mercuride C₁₉H₁₉NO₃I₂Hg·2H₂O, mp 240°C (water).All-Union Scientific-Research Institute of Medicinal Plants, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 676–680, September–October, 1979.     

Über die Silbergermanate Ag4Ge9O20 und Ag2Ge4O9

Zusammenfassung Der Germanat-Zeolith Ag₃HGe₇O₁₆·4 H₂O wird durch Ionenaustausch aus dem isotypen Ammonium-Zeolith hergestellt. Nach Dehydratation des Ag-Zeoliths bildet sich bei 460°C das zuMe ₄Ge₉O₂₀ (Me=Na, K) isotype Ag₄Ge₉O₂₀. Durch Erhitzen auf 650°C entsteht das zuMe ₂Ge₄O₉ (Me=Na, K, Rb, Tl) isotype Ag₂Ge₄O₉. Oberhalb 760°C erfolgt unter Dissoziation die Bildung von metallischem Silber und GeO₂ (Rutilform).

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The zeolithic germanate Ag₃HGe₇O₁₆·4 H₂O has been prepared by ion-exchange from the analogous ammonium compound. After dehydration at 460°C Ag₄Ge₉O₂₀ is formed, which is isostructural withMe ₄Ge₉O₂₀ (Me=Na, K). By heating up to 650°C Ag₂Ge₄O₉ is obtained, having the structure ofMe ₂Ge₄O₉ (Me=Na, K, Rb, Tl). Above 760°C the compound decomposes into silver, oxygen and GeO₂ (rutile).

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121Sb,123Sb AND209Bi NQR spectra of antimony(III) and bismuth(III) ethylenediaminetetraacetate compounds

A¹²¹Sb,¹²³Sb, and²⁰⁹Bi NQR spectral study was carried out on SbHEDTA·nH₂O, BiHEDTA·nH₂O(n=2, 0), MBiEDTA·H₂O, M₂Bi(OH)EDTA·nH₂O (n=3,1, M=K,NH₄), and K₂BiFEDTA·3H₂ O. Piezoelectric properties were found in MHEDTA·2H₂O (M=Sb,Bi) and SbHEDTA. The temperature range of the piezoelectric phase for SbHEDTA was found to be 100–270 K.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1915–1918, August, 1989.     

Thermal properties and thermochemistry of lanthanide chromates

The behavior of chromates Ln₂(CrO₄)₃·7H₂O and Rb₅Ln(CrO₄)₂ (Ln = La, Pr, Nd, Sm, and Gd) was studied by derivatography as they were heated in air in a temperature interval of 300–1470 K. The high temperature enthalpies of LaCrO₃ and YCrO₃ at 865–1350 K and enthalpies of solution of La₂(CrO₄)₃·7H₂O in a solution of nitric acid at 298 K were measured by calorimetric methods. The standard enthalpies of formation were calculated for some compounds of composition Ln₂(CrO₄)₃·2H₂O and LnCrO₃.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 290–295, February, 2005.     

Crystal Structure and Dynamics of Water Molecules and Fluoride Ions in NaKSbF5·1.5H2O and NaRbSbF5·1.5H2O

The atomic structures of crystal hydrates were determined at 173 and 293 K for NaKSbF₅·1.5H₂O (I) and at 293 K for NaRbSbF₅·1.5H₂O (II). Crystals I and II are isostructural, space group . The dynamics of water molecules and complex ions was investigated by NMR in the range 170-440 K. The existence of a phase transition of order–disorder type in compounds I and II was established. A mechanism leading to the diffusion motion of fluoride ions in II is suggested, and dehydration of the compounds is considered.     

Field-evaporation mass spectroscopy applied to crown ether complexes with alkali and alkaline-earth metals

Field evaporation from solution has been used to detect crown-ether 15K5 and 18K6 coordination compounds formed with Na⁺, K⁺, Cs⁺, Ba²⁺ and Ca²⁺ in aqueous solution, both hydrated and unhydrated; the Ca²⁺·18K6·(H₂O)_n (n=0, 1, 2,...) compounds have been observed before. 18K6 present in the solution greatly increases the yields of 18K6 compounds with the dissociation products from Ba(NO₃)₂. The detection limits for 15K5 and 18K6 combined with Na⁺, K⁺, and Cs⁺ are approximately the same at 10^–7 g.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 24, No. 2, pp. 239–242, March–April 1988.     

Structural and thermal interpretation of the synergy and interactions between the fire retardants magnesium hydroxide and zinc borate

The mechanism of cooperative action of commercial fire retardants is interpreted as resulting from specific chemical reaction and phase changes. This investigation focuses on the thermally initiated interactions between two forms of commercially available fire retardant compounds. The fire performance of a polyolefin with a metal hydroxide fire retardant, magnesium hydroxide, can significantly reduce the heat release rate through absorption of heat during conversion to its metal oxide. Formation of water, followed by vaporisation, decreases heat and dilutes volatiles from polymer degradation. The second form of fire retardant compounds are zinc borates (2ZnO·3B₂O₃·3H₂O and 4ZnO·B₂O₃·H₂O), that undergo dehydration with increasing temperature. Differential thermal analysis and wide-angle X-ray spectroscopy indicated that various structural changes occurred during heating. Endothermic transitions were observed for all components, while zinc borate (2ZnO·3B₂O₃·3H₂O) showed an exothermic crystallisation transition at relatively high temperature. The exotherm was modified by the development of a new crystalline phase, magnesium orthoborate (3MgO·B₂O₃) that formed on reaction with magnesium oxide (MgO) at temperatures greater than 500 °C. Formation of crystalline zinc oxide (ZnO) was also detected. From zinc borate (4ZnO·B₂O₃·H₂O), ZnO was primarily formed. No new crystalline phases were observed in the presence of MgO over the temperature range investigated.