Exchangeable fraction of elements in alluvial sediments under waste disposal site (Zagreb, Croatia)

Concentrations of Ag, Ba, Cd, Ce, Cs, Co, Cr, Eu, Fe, Rb, Sc, Sr, Th, and Zn exchangeable fractions were determined in alluvial sediments at waste disposal site area in the vicinity of water-well field. Samples have been leached with 0.5M NH₄Cl at a sample/solution ratio of 120 during 24 hours without shaking. INAA of dry NH₄Cl residues show that the concentrations of exchangeable elements determined in the most of the sediments below the wastes have natural levels. Ag, Ba and Sr are readily exchangeable; Rb, Cs and Zn have lower exchangeability, while Cd, Ce, Th, Sc, Eu, Cr, Fe and Co are rather immobile. Extremely high total and exchangeable silver concentration was found at 6.5–6.8 meters below waste in the aerated layer occasionally under the water table. Exchangeable concentrations in deeper water-bearing sediment layers are not elevated. Due to this, one can presume that the upper sediment layers act as chemical filter generally preventing the infiltration from overlying wastes into water-bearing layers.     

Kinetics of the yttrium fluoride electroreduction in chloride melts

To establish the effect of the nature of supporting electrolytes KCl; K, Na/Cl; K, Na, Cs/Cl; and K, Na, Ba/Cl on the electrochemical deposition of yttrium from melts, the electroreduction of yttrium fluoride in the said melts is studied by a linear voltammetry method. The discharge of ions Y³⁺ in all the melts occurs via one stage. The diffusion coefficients, activation energy, product of transfer coefficients and the number of electrons n , diffusion layer thickness, diffusion constant, and rate constant of charge transfer are determined.Translated from Elektrokhimiya, Vol. 41, No. 1, 2005, pp. 48–53.Original Russian Text Copyright © 2005 by N. Gasviani, Dzhaparidze, Kipiani, S. Gasviani, Abazadze.     

Codimerization of C6-C10 α-olefins with butadiene using zirconium complexes

Conclusions The codimerization of butadiene with linear C₆-C₁₀ -olefins on a ZrCl₄-AlEt₂Cl catalyst leads to the 1,4-addition products of the-olefin to butadiene.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1410–1412, June, 1981.     

Synthesis and characterization of cyclopentadienyl transition metal halides,part I,vanadium halides

Summary Reactions between -Cp₂V and PX₃ (X=Cl, Br or I) yield the corresponding dihalogenated derivatives -Cp₂VX₂ (X=Cl, Br or I). The oxidative addition of ICl and IBr to -Cp₂V gives mixed halogenated derivatives -Cp₂VIX (X=Cl or Br). All the compounds have been characterized by elemental analyses, magnetic moment measurements and i.r. and e.p.r. spectra.     

Elektrische Leitfähigkeiten geschmolzener Salzmischungen aus Erdalkalimetallbromiden und Alkalimetallbromiden

Electrical Conductivity of Molten Alkaline Earth Bromide - Alkali Bromide Salt Mixtures The temperature and concentration dependence of the specific electrical conductivity was measured for binary CaBr₂? MBr(M?Li, K, Rb, Cs) and KBr–(Sr, Ba)Br₂ mixtures. In the systems CaBr₂? (K, Rb, Cs)Br and SrBr₂–KBr minima were found on the isotherms of the specific and molar electrical conductivity at the concentration x ≈0,5.     

Radiochemical determination of Caesium-137, strontium-89,90 and barium-140 in milk and bone ash

Summary A method for the determination of radiocaesium, radiostrontium, radiobarium in milk and bone ash is described. An alkaline fusion of ash followed by leaching with water provides for the preliminary separation of radiocaesium. After dissolution of leaching residue in hydrochloric acid and sorption on Dowex 50 W, X-8, radioyttrium (rare earths fission products), magnesium and calcium are eluted with 1.0 M ammonium lactate, pH 7.5. Radiostrontium, radiobarium and radium are separated by elution with 0.15 M ammonium citrate, pH 7.5. ¹³⁷Cs is isolated as Cs-dipicrylaminate, ⁸⁹Sr/⁹⁰Sr as SrCO₃, ¹⁴⁰Ba as BaCO₃ and counted on a low-background beta-counter. For determined radionuclides the average chemical yields amount to 80%. The limits of detection for ¹³⁷Cs, ⁹⁰Sr, ¹⁴⁰Ba are 0.02 pCi/g with a 10 g sample of milk ash and 0.04 pCi/g with a 4 g sample of bone ash, respectively.

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Radiochemische Bestimmung von Caesium-137, Strontium-89,90 und Barium-140 in Milch- und Knochenasche

Zusammenfassung Zur Vorabtrennung von Radio-Caesium wird die Ascheprobe alkalisch geschmolzen und dann mit Wasser ausgelaugt. Nach Auflösung des ausgelaugten Rückstandes in Salzsäure und Sorption an Dowex 50 W, X-8 werden Yttrium (Spaltprodukte der Seltenen Erden), Magnesium und Calcium mit 1,0 M Ammoniumlactat, pH 7,5 eluiert. Radio-Strontium, Radio-Barium und Radium werden durch Elution mit 0,15 M Ammoniumcitrat, pH 7,5, abgetrennt. ¹³⁷Cs wird als Cs-Dipikrylaminat isoliert, ⁸⁹Sr/⁹⁰Sr als SrCO₃,¹⁴⁰Ba als BaCO₃; gemessen wird in einem Beta-Antikoincidenzzähler. Für die bestimmten Radio-Nuklide beträgt die durchschnittliche Rückgewinnung 80%. Die unteren Nachweisgrenzen für ¹³⁷Cs, ⁹⁰Sr, ¹⁴⁰Ba betragen bei einer 10 g-Milchasche-Probe 0,02 pCi/g und bei einer 4 g-Knochenasche-Probe 0,04 pCi/g.

     

Precipitation separation of lead and calcium,strontium, barium from acidic solutions using crown ether and tungstosilicic acid

It was found that lead reacts with 18-crown-6 (L) and tungstosilicic acid (H₄A) in acidic solutions and a compound with low solubility is formed what was confirmed by radiometric titration methods. Coprecipitation of complexion cation of PbL²⁺ with similar complexion cations of calcium, strontium and barium was studied. Formation of low soluble salts was utilized for separation of Pb from Ca, Sr and Ba from 1 mol·dm^–3 HNO₃. The ratio of Pb/Ca, Pb/Sr and Pb/Ba in the precipitation or separation factors S_pb/M undoubted depends on the ratio of the stability constants of lead and metals with 18C6 (_Pb/_M), what can be used for determination of more precise constant stability _M.     

A cation-exchange study of stability constants of complexes formed between bismuth/III/ and nitrate or chloride ions

A cation-exchange method was used for determining the stability constants of complexes formed between Bi/III/, present in tracer concentrations /ca. 10^–11M Bi/, and nitrate ion or chloride ion in 1.OM H/ClO₄, NO₃/ or 1.OM H/Cl, ClO₄/ solutions, respectively. The successive formation constants were calculated using the distribution data. The resulting 1g ₁, 1g ₂, and 1g ₃ values were 0.74, 1.22, and 1.54 for 1.OM H/ClO₄, NO₃/ solutions, and 2.36, 3.61, and 4.95 for 1.OM H/Cl, ClO₄/ solutions, respectively.     

Fallout analysis of atmospheric water precipitations

Summary A rapid ion-exchange method for the determination of ¹⁴⁴Ce, ¹³⁷Cs, ⁸⁹Sr, ⁹⁰Sr and ¹⁴⁰Ba in 2–30 liter samples of atmospheric water precipitations is described. The samples, containing up to 300 mg of calcium, are sorbed on a specially shaped column filled with Dowex 50, X-8 or Dowex 50W, X-8. Radio-cerium and radio-caesium are stripped from the column with 0.6 M ammonium glycolate/ 0.2 M NaCl, pH 5, radio-strontium and radio-barium with 0.15 M ammonium citrate, pH 7.5. The isolated radio-nuclides are counted on a low-background beta-counter: ¹⁴⁴Ce as CeO₂, ¹³⁷Cs as Cs-dipicrylaminate, ⁸⁹Sr/⁹⁰Sr as SrCO₃, ⁹⁰Y as Y₂O₃, and ¹⁴⁰Ba as BaCO₃. The mean chemical yields amount to 95% for cerium, 85% for caesium, 95% for strontium, 95% for yttrium and 65% for barium. With parallel determinations at levels of a few picocuries, the deviations of the results from the respective mean values generally do not exceed ± 5%. With a 30 l sample the limit of detection amounts to 0.005 Ci/l for ¹⁴⁴Ce, 0.006 Ci/l for ¹³⁷Cs, 0.005 Ci/l for ⁹⁰Sr, and 0.006 Ci/l for ¹⁴⁰Ba.

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Zusammenfassung Es wird eine schnelle Ionenaustauschmethode für die Bestimmung von ¹⁴⁴Ce, ¹³⁷Cs, ⁸⁹Sr, ⁹⁰Sr und ¹⁴⁰Ba in 2–30 l Proben von atmosphärischen Wasser-Niederschlägen beschrieben. Die Proben, mit einem Calciumgehalt bis zu 300 mg, werden in eine besonders gestaltete, mit Dowex 50, X-8 oder Dowex 50 W, X-8 gefüllte Säule eingewaschen. Radio-Cer und Radio-Caesium werden mit 0,6 M Ammoniumglykolat/0,2 M NaCl, pH 5, Radio-Strontium und Radio-Barium mit 0,15 M Ammoniumcitrat pH 7,5 eluiert. Die isolierten Radio-Nuklide werden in einem Beta-Antikoinzidenzzähler gemessen: ¹⁴⁴Ce als CeO₂, ¹³⁷Cs als Cs-dipikrylaminat, ⁸⁹Sr/⁹⁰Sr als SrCO₃, ⁹⁰Y als Y₂O₃ und ¹⁴⁰Ba als BaCO₃. Die mittlere Rückgewinnung der zugesetzten Träger beträgt für Cer 95%, 85% für Caesium, 95% für Strontium, 95% für Yttrium und 65% für Barium. In Parallelbestimmungen mit Gehalten von einigen Ci/l, überschreiten die Abweichungen der Ergebnisse von den entsprechenden Mittelwerten im allgemein nicht 5%. Bei einer 30 l-Probe beträgt die untere Nachweisgrenze 0,005 Ci/l für ¹⁴⁴Ce, 0,006 Ci/l für ¹³⁷Cs, 0,005 Ci/l für ⁹⁰Sr und 0,006 Ci/l für ¹⁴⁰Ba.

     

Trends in the NMR chemical shifts of F19 and the NQR spectra of Cl35 and Br79 in halonitroalkanes

F¹⁹ NMR chemical shifts _F are reported for fluoronitroalkanes, which are found to show a nearly linear relation to the NQR shifts for the chlorine and bromine analogs. The spin-spin coupling constant J_F-N also indicates that the Hal-C-N angles vary little in the series Hal_nC(NO₂)_4-n. The empirical relation can be used to predict the properties of new halonitromethanes. The observed trends in _F and _Cl when H is replaced by X (with X=Cl, F, or NO₂) for the halonitromethanes indicate the sequence NO₂, F, Cl as regards shift _F towards weaker fields, but the sequence F, Cl, NO₂ as regards shift _Cl towards higher NQR frequencies. The deviations from a linear relation for mixed halonitromethanes containing electron-donor groups indicate either that the distortion of the tetrahedral angle varies with the halogen or that conjugation effects for F¹⁹ NMR are different from those for Cl³⁵ and Br⁷⁹ NQR.     

Cobalt(III) complexes with aminothiolates

Summary This article describes some complexes of cobalt(III) with -mercaptopropylamine,N, N-dimethyl--mercaptopropylamme andN,N-dimethyl--mercaptoethylamine. The compounds are of stoichiometry [Co(ligand)₃], [Co₃(ligand)₆]_X (X=Cl or Br) and [Co(ligand)₃]X₃ (X=Cl or ClO₄). -Mercaptopropylamine yields both chelated and non-chelated compounds while theN,N-dimethyl derivatives yield only non-chelated complexes. This behaviour contrasts with the results obtained with nickel(II).     

Lewis-Base Adducts of Group 11 Metal(I) Compounds. LXXV Structural Systematics of the Binuclear Copper(I) Halide: 1,5-Cyclooctadiene (‘cod’) 2:2 Adducts, [(cod)Cu(μ-X)2Cu(cod)], X = Cl, Br, I

Adducts of 1,5-cyclooctadiene (cod) with the copper(I) halides, CuX (X = Cl, Br, I) of 1:1 stoichiometry are confirmed as binuclear species of [(cod)Cu(-X)₂Cu(cod)] by single crystal X-ray studies, those for X = Cl, I being executed at low-temperature. The study for X = Cl is a redetermination, exposing disorder in one of the copper atom sites; a similar redetermination of [Cu(cod)₂](ClO₄) shows disorder in respect of one of the ligands. Bonding parameters are compared with those for other Lewis-base analogues.     

Catalysis by porous heteropoly compounds

This paper attempts to review recent works on catalysis of porous heteropoly compounds. The salts of heteropolyacids having Keggin structure with large cations like Cs⁺ are porous materials. For Cs hydrogen salts, the pore width can be controlled by the Cs content. Cs_2.5H_0.5PW₁₂O₄₀ has the largest amount of protons on the surface among the acidic Cs salts and possesses pores with bimodal distribution in the micro and meso region. Efficient performances were demonstrated for acid-catalyzed reactions such as skeletal isomerization of -butane in solid-gas system, alkylation and acylation in solid-liquid system, and hydrolysis and hydration in solid-water system. A microporous salt, Cs_2.2H_0.8PW₁₂O₄₀, exhibited reactant shape selectivity towards direct decomposition of esters. Furthermore, an ultramicroporous bifunctional catalyst, Pt–Cs_2.1H_0.9PW₁₂O₄₀ of which the pore width is around 5 Å, exhibits reactant shape selectivity for hydrogenation of alkenes and oxidation of hydrocarbons, and product shape selectivity for skeletal isomerization of -butane.     

Correlation of nucleae quadrupole resonance frequencies with some chemical constants in the aliphatic series

Linear relationships are established between the nuclear quadrupole resonance frequencies of alkyl chlorides, RCl, on the one hand, and the pK_a values of RCOOH and RNH₂ as well as the Taft ^* constants, on the other hand. Similar linear correlations were found between the NQR frequencies of the substituted compounds XCH₂Cl and the pK_a of XCH₂COOH, XCH₂NH₂, XCH₂OH, as well as the ^* constants of XCH₂ radicals, where X are electronegative substituents. X substituents with unshared electron pairs (RO, RS, F, Cl, Br) are an exception; nevertheless, the deviation of these points is regular and depends linearly on the resonance parameters _R ⁰ or _R of the X substituents. The relationships can be used for an approximation of the ionization constants of a number of fatty acids, for the calculation of the Taft ^* constants of radicals R and XCH₂ and of the resonance parameters _R ⁰ and _R of X substituents with an accuracy which in many cases is in no way inferior to that of the experimental values, and also for the approximate evaluation of the ionization constants of XCH₂NH₂ amines and XCH₂OH alcohols.     

Trace characterization of high-purity nickel by instrumental and radiochemical neutron activation analysis

Summary The high activity of the radionuclides ⁶⁵Ni (t_1/2=2.52 h) and ⁵⁸Co (t_1/2=70.8 d) imposes severe limitations on the performance of direct instrumental neutron activation analysis of nickel. The extent of the interference of the ⁵⁸Co depends on the ratio of the fluxes of the fast and thermal neutrons. A method of selective removal of cobalt, based on extraction with -nitroso--naphthol has been developed for the purpose of radiochemical NAA. Separation yields have been determined for 36 elements. The detection limits obtainable with both the instrumental and the radiochemical method are <10^–4 g/g for the elements Au, Eu, Ir, La, Sc and Sm, between 10^–4 and 10^–3 g/g for Cr, Cs, Hf, Hg, Lu, Re, Sb, Ta, Th, Tm and Yb, between 10^–3 and 10^–2 g/g for As, Ag, Br, Ce, Ga, Na, Ru, Se, W and Zn, and in the range 0.01–1 g/g for Ba, Cd, Co, Fe, In, K, Mo, Nd, Pd, Rb, Sn, U and Zr.     

Reaction of chloromercuriocobaltacarborane with derivatives of the undecaborate anion

The reactions of the undecaborate anion Cs⁺C₂B₉H₁₂ ^– (1) and exo-nido-ruthenacarborane exo-nido-5,6,10-[Cl(Ph₃P)₂Ru]-5,6,10-(-H)₃-10-H-7,8-C₂B₉H₈ (2) with the 9-chloromercurated cobaltacarborane, viz., 3-(⁵-Cp)-9-ClHg-3,1,2-CoC₂B₉H₁₀ (3), afforded Cs[10-{3"-(⁵-Cp)-3",1",2"-CoC₂B₉H₁₀-9"-Hg}-7,8-C₂B₉H₁₁] (4) and 5,6,10-exo-nido-[Cl(Ph₃P)₂Ru]-5,6,10-(-H)₃-10-{3"-(⁵-Cp)-3",1",2"-CoC₂B₉H₁₀-9"-Hg}-7,8-C₂B₉H₈ (5), respectively. The latter compound exists as two isomers. Compound 5 was prepared also by the reaction of compound 4 with Ru(PPh₃)₃Cl₂.     

INAA of IAEA-331 (spinach), SRM,for 40 elements

Forty elements in IAEA-331 (Spinach), an intercomparison material, have been determined using NAA. Among them, 30 elements, Ag, Al, Ba, Br, Ca, Ce, Cl, Co, Cr, Cs, Eu, Fe, Hf, K, La, Mg, Mn, Na, Ni, Rb, Re, Sc, Se, Sr, Ta, Tb, Th, V, Zn and Zr were determined by INAA. A series of simple and quantitative radiochemical separation procedures were established for the determination of ten additional elements. Cd, Lu, Mo, Sb, Sm, Yb, U were determined by removing the major interfering nuclide⁸²Br. Cu was determined by 0.048M NaDDTC/CHCl₃ extraction from 1M HCl medium. As and P were determined using an inorganic exchange column of acid aluminium oxide (AAO). Integral counts from 80 keV to 130 keV contributed by Bremsstrahlung from³²P -were used to evaluate the content of phosphorus.     

Copper (II)-thiolate complexes with novel tripodal- and tetrapodal-like benzimidazoles

Summary The tripodal copper(II) thiolate complexes Cu(L1)(Cl)-2H₂O and Cu(L1)(mim)(Cl) [H(L1) = N-(2-mercaptoethyl)-N,N-bis (pyrid-2-ylmethyl)amine and mim = N-methylimidazole] have been isolated. Both contain monomeric copper(II) and display two ligand field bands and axial cryogenic e.p.r. spectra, suggesting a squarebased geometry. A copper(II) thiolate complex Cu(L2)(Cl)-H₂O [H(L2) = N-(2-mercaptoethyl)-N,N,N-tris(benzimidazol-2-ylmethyl)-1,2-ethanediamine] with a CuN₅S chromophore has been also isolated. It exhibits only one ligand field band and an axial cryogenic e.p.r. spectrum, consistent with a distorted tetragonal coordination geometry. All the thiolates display intense S^– Cu^II charge transfer bands in the u.v. region, suggesting equatorial thiolate coordination. All of the complexes exhibit irreversible electrochemical behaviour.     

Zur Chemie und Strukturchemie der Phosphide und Polyphosphide. 26. Dibariumheptaphosphidchlorid Ba2P7Cl,eine Verbindung mit dem polycyclischen Anion P

Chemistry and Structural Chemistry of Phosphides and Polyphosphides. 26. Dibariumheptaphosphidechloride Ba₂P₇Cl, a Compound with the Polycyclic Anion P Ba₂P₇Cl is formed by the synthesis of Ba₃P₁₄ from the elements in a melt of BaCl₂ (dehydrated) at 1170 K. The compound forms light rubyred platelets which decompose in protic systems immediately to phosphanes. Ba₂P₇Cl crystallizes in the space group P2₁/m with Z = 2 formular units (a = 1172.6(2) pm; b = 682.9(1) pm; c = 633.7(1) pm; β = 95.27(2)°). The structure (964 reflexions hkl, R = 0.035) is related to the NaCl type, in which the half of the anionic positions is occupied by the gravi-centers of the polycyclic anions P. The bond lengths d(P? P) show the typical topological dependence for the anionic heptaphosphanortricyclene system: (d : 226.4 pm in the three-membered ring; 214.5 pm ring to bridge; 217.2 pm bridge to bridge head). The Ba atoms are surrounded by 9 and 10 non metallic atoms, respectively. Cl^? is coordinated tetrahedrally by Ba.     

Halogen oxidation and nitrosylation of some aldimine and ketimine carbonyl complexes of chromium and molybdenum

Summary The halogen oxidation and nitrosylation of cis-[(SB)M-(CO)₄] [M = Cr or Mo, SB = N,N-ethylenebis(p-tolualideneimine), N,N-ethylenebis(p-N,N-dimethylaminobenzalideneimine) or N,N-ethylenebis(methyl-p-methoxyphenylketimine); M = Mo, SB = N,N-ethylenebis-(cinnamylideneimine) or N,N-ethylenebis(methyl-p-methylphenylketimine)] have been studied. Halogenation of [(SB)Cr(CO)₄] yielded [(SB)CrX₂] (X = Cl, Br or I) where-as [(SB)Mo(CO)₄] gave [(SB)Mo(CO)₃X₂] (X = Br or I) and [(SB)MoX _x ] (X = I, n = 2; X = Cl or Br, n = 4). NOCl produced [(SB)Cr(NO)₂Cl₂] and [(SB)Mo(CO)₂(NO)Cl] when reacted with the corresponding [(SB)M(CO)₄]. The complexes were characterized by physico-chemical and spectroscopic measurements.