The phase diagram and supercooling conditions for the Ca(NO3)2−CaCl2−H2O system

The liquidus temperature and induction periods were measured for crystallization in a system of calcium nitrate, calcium chloride, and water over a concentration range of 5–20 mole% Ca(II), i.e., R=4–18 [R=moles H₂O/moles Ca(II)] and y_cl=0–1 [y_cl=moles Cl^–/moles (NO ₃ ^– +Cl^–)]. A ternary phase diagram was constructed, and qualitative dependences of the supercooling at which the solution began to crystallize on the system composition were found. A wide range of stability toward crystallization was found for solutions withR=4–10 and y_cl=0–0.7 The relationships between the system stability toward crystallization and the viscosity, glass-transition temperature, and the liquidus temperature are discussed.     

Ionic Lithium-Conducting Solid Li2S–Sb2S x Electrolytes

The electroconductivity of lithium-containing solid electrolyte Li₂S–Sb₂S₃is studied. At room temperature it equals (1.5–2.5) × 10^–4 S cm^–1. The activation energy for conduction, determined from the temperature dependence of the electroconductivity, is 0.35–0.43 eV.     

1, 2-Dithiolium salts

A new method for the synthesis of 1, 2-dithiolium hydrogen sulfates by the oxidation of 1, 2-dithiole-3-thiones with hydrogen peroxide in acetic acid has been developed. From 4-(p-tolyl) 1, 2-dithiolium hydrogen sulfate a series of salts containing anions of inorganic, heteroorganic, and organic acids (Cl^–, Br^–, I^–, ClO ₄ ^– , CNS^–, VO ₃ ^– , HMoOO ₄ ^– , S₂O ₃ ^2– , S₂O ₈ ^2– , Cr₂O ₇ ^2– , Fe(CN) ₆ ^3– , Fe(CN) ₆ ^4– , B(C₆H₅) ₄ ^– , F₃CCOO^–, C₆H₂(NO₂)₃O^–) has been obtained. 4-(p-tolyl)-1, 2-dithiolium salts containing the anions NO ₂ ^– , NO ₃ ^– , ClO ₃ ^– , BrO ₃ ^– , SO ₃ ^2– , SO ₄ ^2– , S₂O ₅ ^2– and Cl₃CCOO^– dissolve in water and do not precipitate in double decomposition reactions. The reactions of 4-(p-tolyl)-1, 2-dithiolium hydrogen sulfate with sodium sulfite, disulfide, and hydrogen sulfide lead to the formation of bis[4-(p-tolyl)-1, 2-dithiol-3-yl] sulfide and disulfide and the sodium salt of 4-(p-tolyl-1, 2-dithiole-3-thiol, respectively. The reaction of 4-(p-tolyl)-1, 2-dithiolium hydrogen sulfate with solutions of salts of the alkali metals containing the anions of weak acids F^–, CNO^–, HCO ₃ ^– , CO ₃ ^2– , B₄O ₇ ^2– , HAsO ₄ ^2– , PO ₄ ^3– , CH₃COO^–, ClCH₂COO^–, etc.) forms bis[4-(p-tolyl)-1, 2-dithlol-3-yl] oxide. [8, Table 3].For part I, see [1].     

1, 2-Dithiolium salts

4-(p-Tolyl)-1,2-dithiolium hydrogen sulfate (I) is not a specific analytical reagent for the majority of anions, and it is not very selective, only in a few cases attaining pD=5 (MoO₄ ^2–, [Hg(CNS)₄]^2–, and [PtCl₆]^2–). All strongly colored anions give colored salts with I. Among the weakly colored anions, the [Fe(CN)₆]^4– anion is worthy of special note, since it forms a deeply colored salt with I. This anion can be detected with I in the presence of Cl^–, Br^–, I^–, CNS^–, ClO₄ ^–, IO₄ ^–, and ReO₄ ^–, which form fairly readily soluble salts with I. Compound I is also a fairly selective reagent for Pd²⁺ in acid solution (pD=5).For part II, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 5, pp. 595–597, May, 1970.     

Die Kristallstruktur von Zr2Al und Hf2Al

Zusammenfassung Im Zweistoff: Zr–Al bzw. Hf–Al werden zwei neue Kristallarten Zr₂Al und Hf₂Al mit CuAl₂-Struktur nachgewiesen; die Parameter sind:a=6,840 bzw. 6,76₂ undc=5,49₀ bzw. 5,37₄ kX·E. In den Dreistoffen: Zr–Al–Si und Hf–Al–Si besteht jeweils ein lückenloser Übergang zwischen den isotypen Phasen Zr₂Al und Zr₂Si bzw. Hf₂Al und Hf₂Si.     

Polarographic and voltammetric determination of trace amounts of 2-nitronaphthalene

The polarographic behaviour of 2-nitronaphthalene was investigated by DC tast polarography (DCTP) and differential pulse polarography (DPP), both at a dropping mercury electrode, and differential pulse voltammetry and adsorptive stripping voltammetry, both at a hanging mercury drop electrode. Optimum conditions have been found for the determination of 2-nitronaphthalene by the given methods in the concentration ranges of 2×10^–6–1×10^–4, 2×10^–7–1×10^–4, 1×10^–8–1×10^–4 and 2×10^–9–1×10^–8 M, respectively. Practical applicability of these techniques was demonstrated by the determination of 2-nitronaphthalene in drinking and river water after its preliminary separation and preconcentration using liquid–liquid and solid-phase extraction with limits of determination of 3×10^–10 M (drinking water) and 3×10^–9 M (river water).     

Untersuchungen an Kristallhydraten anorganischer Salze, 8. Mitt. Interpretation der Schwingungsspektren vonM(BF4)2·6H2O fürM=Fe2+, Co2+, Ni2+

The infrared and Raman spectra were recorded in the range 4000–160 cm^–1 forM(BF₄)₂·6 H₂O whereM=Fe²⁺, Co²⁺, Ni²⁺. The spectroscopic data support the X-ray structural data in showing that in the crystal hydrates studied two kinds of hydrogen bonds are present: H₂O...H₂O and OH₂... F₄B^–. The energies and molecular force constants (f _OH and fH₂O) andr _OH for OH₂...F₄B^– were calculated for the three crystal hydrates. It was found that the bond OH₂... F₄B^– is comparatively weak, with mean energy 3.7–3.3 kcal/mol. Two types of water molecule with different structures are existing as the first are participating in H₂O...H–O–H...F₄B^– and the second in BF₄ ^–...H–O–H...F₄B^–.     

Mittlere Schwingungsamplituden des ClO2F2 −-Anions

The mean amplitudes of vibration of the ClO₂F₂ ^– anion have been calculated using known spectroscopic data. The results are briefly discussed and comparisons are made with other species containing Cl–O and Cl–F bonds.     

Reaction of dialkylboric anhydrides with 2-amino- and 2-hydroxypyridine

Conclusions The anhydrides of dialkylboric acids react with 2-aminopyridine at 150–190° and with 2-hydroxypyridine at 100–170° to give cyclic coordination compounds of boron and saturated hydrocarbons.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1919–1921, August, 1977.     

Researches on 2, 1, 3-thia- and selenadiazole

4-Hydroxy-, 4-hydroxy-5-methyl-, 4-hydroxy-7-methylbenzo-2,1,3-thiadiazoles are polymorphous.4-Hydroxybenzo-2,1,3-thiadiazole (I), 4-hydroxy-5-methyl- and 4-hydroxy-7-methylbenzo-2, 1, 3-thiadiazoles (II and III) melt at 114–115°, 110–112°, 100–102° C, respectively, after recrystallization from water [2–4], but after recrystallization from petrol ether [5] they melt at 128–129°, 124–125°, and 119–120° C [5]. In this connection we recrystallized these phenols repeatedly from petrol ether after recrystallizing them from water, and their melting points rose as expected [5]. On the other hand, the compounds with melting points 128–129°, 124–125°, 119–120° C (ex petrol ether), after repeated crystallization from water melted at 114–115°, 110–112°, 100–102° C, respectively.For Part XXXVIII see [1].     

Deprotonation of unsaturated fluoroethers,CH2=CHCH2OCF2CHXCF3 and CH≡CCH2OCF2CHXCF3 (X=COF and SO2F)

2-Fluorocarbonyl- and 2-fluorosulfonylpentafluoropropenes upon cooling add allyl and propargyl alcohols at the C=C bond to form strong CH-acids (I)–(IV). These CH-acids react with BF₃sdNEt₃ under mild conditions and are converted to 2-fluorocarbonyl- and 2-fluorosulfonyl-2-trifluoromethyl-substituted unsaturated acid fluorides (V)–(VIII). The conditions, rate, and high selectivity of these reactions support the hypothesis that the formation of acid fluorides (V)–(VIII) involves a [3,3]-sigmatropic rearrangement of intermediate carbanions (Ia)–(IVa).For preliminary communication, see [1].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1672–1675, July, 1990.     

IR-Spektralanalyse von Gläsern des Systems TeO2−V2O5

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.

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Mit 4 Abbildungen     

Formation Mechanism of O2– Radical Anions in the Adsorption of NO + O2 and NO2 + O2 Mixtures on ZrO2 According to EPR and TPD Data

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.     

An aqueous thermodynamic model for a high valence 4∶2 electrolyte Th4+−SO 4 2− in the system Na+−K+−Li+−NH 4 + −Th4+−SO 4 2− −HSO 4 − −H2O to high concentration

An aqueous thermodynamic model that is valid from zero to high concentration is proposed for the Na⁺–K⁺–Li⁺–NH ₄ ⁺ –Th⁴⁺–SO ₄ ^2– –HSO ₄ ^– –H₂O system. The model is based on the aqueous ion-interaction model of Pitzer and coworkers. The thorium sulfate complex species Th(SO₄)₂(aq) and Th(SO₄) ₃ ^2– are also included in the model. The final thermodynamic model presented here accurately predicts all reliable thermodynamic data, including solvent extraction and solubility data, for the Na⁺–K⁺–Li⁺–NH ₄ ⁺ –Th⁴⁺–SO ₄ ^2– –HSO ₄ ^– –H₂O system to high concentration. The aqueous thermodynamics of high-valence (3:2, 4:2), electrolytes are complicated by very strong specific ion interactions or ion pairing in dilute solution and by an effective redissociation of aqueous complex species at high concentration. Methods of treating these complications, in terms of valid aqueous thermodynamic models, are discussed in detail for the high-valence Th⁴⁺–SO ₄ ^2– –H₂O system.     

Polarographic behaviour of 2-benzilidenimino-benzohydroxamic acid (2-BIBH) and 2-BIBH-Mo(VI) system

The polarographic behaviour of 2-benzilideniminobenzohydroxamic acid (2-BIBH) solutions and of 2-BIBH solutions in the presence of Mo(VI) have been studied by using differential pulse polarography and cyclic voltammetry. The polarographic characteristics of the resulting waves have been studied and possible mechanisms of the processes involved have been proposed. A linear relationship has been observed betweenI _p and Mo(VI) concentration in the range 2×10^–6 to 1.6×10^–5 M when using 3×10^–4 M 2-BIBH. Standard deviations of 5.6×10^–8 and 1.2×10^–8 M were found for 3×10^–6 and 8 × 10^–6 M Mo(VI), respectively.     

IR-Spektralanalyse von Gl?sern des Systems TeO2?V2O5

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.     

Crystal structure of the organic conductor (BEDT-TTF)3Cl2·2H2O

Institute of Chemical Physics, Academy of Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 31, No. 5, pp. 3–7, September–October, 1990.     

Struktur von Gläsern des Systems TeO2−VO2

Glasses from the TeO₂–VO₂ system and - and -crystalline modifications of TeO₂·VO₂ (TeVO₄) are studied by IR-spectroscopy in the 1400–400 cm^–1 range. Similarity is established in the area near 970 cm^–1 of the spectrum between TeVO₄ glass and the -form. The continuous shift of the band from 970 cm^–1 to 950 cm^–1 with increasing TeO₂ content in the glasses is connected with the indirect influence on the nonbridging V–O bond.It is shown that the local environment of the V in some glasses from TeO₂–VO₂ and TeO₂–V₂O₅ system is similar: VO₅ polyhedra.     

Electrosynthesis of N-tert-Butyl-2-benzothiazolesulfenamide

Conditions for the production of N-tert-butyl-2-benzothiazolesulfenamide (TBBS) in an oxidative condensation of 2-mercaptobenzothiazole and tert-butylamine are determined. The electrosynthesis occurs during electrolysis of a 4.5–5.0 M NaCl solution containing a water-immiscible organic solvent extracting TBBS. The process efficiency is the highest at the following conditions: a 1 : 8 ratio between 2-mercaptobenzothiazole and tert-butylamine, a DSA, a stainless-steel cathode, a current density of 300 A m^–2, and a continuous extraction of TBBS into a 3 : 1 mixture of carbon tetrachloride and acetonitrile. Under these conditions, the TBBS yield is 98–100%, the current efficiency is 74%, the process productivity is 0.9 kg m^–2 h^–1, and the electricity consumption is 1.9 kW h kg^–1. Repeated use of the aqueous phase corrected for the source products jeopardizes neither the process characteristics nor the product quality.     

Water in melts: Raman spectral investigation of the molten Ca(NO3)2·4H2O−KNO3 system

The Raman spectra of molten mixtures of Ca(NO₃)₂\4H₂O–KNO₃ have been examined, covering the concentration range of 0–70 mole% KNO₃. The frequencies in the spectra of the mixtures have been found to change slightly with concentration. Striking variations in the band shapes have been observed in the regions corresponding to the O–H stretching mode (2850–3850 cm^–1) and the v₄-NO ₃ ^– mode (700–750 cm^–). The results are discussed in terms of perturbed quasi-lattice structure for the melt, in which there could be a displacement of water molecules in the first coordination sphere around Ca²⁺ by the NO ₃ ^– ion.