Isomorphism in the (NH4)2Th(NO3)6-K2Th(NO3)6-Rb2Th(NO3)6 system

Syntheses were developed, and compounds of composition (NH₄)_2x K_2y Rb_2z Th(NO₃)₆(x + y + z = 1) were prepared. These compounds were structurally studied using X-ray diffraction and IR spectroscopy. Incomplete miscibility in the solid phase of the title system was found, and the impossibility of existence of a hexanitratothorate complex in the (NH₄)₂Th(NO₃)₆-K₂Th(NO₃)₆ system at 298.15 K and the component molar ratio 1: 3 was demonstrated. Calorimetric standard enthalpies of formation and mixing at 298.15 K were determined. Original Russian Text ? N.G. Chernorukov, A.V. Knyazev, A.A. Sazonov, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 7, pp. 1066–1071.     

Effect of conversion of NO2 into no on the catalytic reduction of NO2 with C3H6 in excess O2

During the reduction of NO₂ by C₃H₆ in O₂ over alumina-supported Au, Rh and Pt it was found that three parallel reactions take place,i.e., reduction of NO₂ to N₂ and N₂O, partial decomposition of NO₂ to NO and oxidation of C₃H₆ to CO and CO₂. In the absence of C₃H₆, the NO₂→NO+O₂ reaction reaches a fast equilibrium on Rh and Pt but not on Au and γ-Al₂O₃. Addition of C₃H₆ to the NO₂+O₂ mixture leads to the formation of NO above equilibrium conversion levels.     

Experimental study of high pressure phase equilibrium of (CO2 + NO2/N2O4) mixtures

Experimental bubble pressure, as well as liquid density of (CO₂ + NO₂/N₂O₄) mixtures are reported at temperatures ranging from (298 to 328.45) K. Experiments were carried out using a SITEC high-pressure variable volume cell. Transition pressures were obtained by the synthetic method and liquid density was deduced from measurement of the cell volume. Correlation of experimental results was carried out without considering chemical equilibrium of NO₂/N₂O₄ system. (Liquid + vapour) equilibrium was found to be accurately modelled using the Peng–Robinson equation of state with classical quadratic mixing rules and with a binary interaction coefficient k_ij equal to zero. Nevertheless, modelling of liquid density values was unsatisfactory with this approach.     

Standard enthalpy of formation of (NO2)2[NiF6](cr)

The enthalpies of interactions of (NO₂)₂[NiF₆](cr) with water and aqueous KOH, enthalpies of solution of KF(cr) in dilute aqueous solutions of KNO₃ and KOH, and enthalpy of mixing of solutions of NiF₂, HNO₃, and HF were measured at 298.15 K using isothermic-shell calorimeters. Based on the obtained data and values in the literature, the standard enthalpy of formation of the compound under study was determined by two independent methods: Δ_f H°(NO₂)₂[NiF₆](cr) = −1099 ± 9 kJ/mol.     

Crystal and molecular structure of (NH4)2[UO2(NO3)4] and [(NH4)(18C6)]2[UO2(NO3)4]

Single crystals of diammonium tetranitratouranylate (NH₄)₂[UO₂(NO₃)₄] (I) and a new diammonium tetranitratouranylate complex with 18-crown-6 [(NH₄)(18C6)]₂[UO₂(NO₃)₄] (II) have been synthesized by the reaction of diaquadinitratouranyl tetrahydrate with ammonium nitrate in a nitric acid solution and the reaction of the same reagents with 18C6 in an ethanol solution, respectively. The X-ray diffraction analysis of compounds I and II has been performed. Crystals of compounds I and II are monoclinic, Z = 2, space group P2₁/n, a = 6.4075(5) ?, b = 7.7851(7) ?, c = 12.4461(12) ?, β = 101.239(1)°, V = 608. 94(9) ?³ for compound I and a = 10.542(9) ?, b = 8.590(8) ?, c = 22.5019(19) ?, β = 101.632(1)°, V = 2058.3(3) ?³ for compound II. The [UO₂(NO₃)₄]²⁻ complex anion in compounds I and II contains two monodentate and two bidentate cyclic nitrato groups, and the coordination number of uranyl is 6. The 18C6 molecule in the structure of compound II has the classic crown conformation and combined with the ammonium ion by three hydrogen bonds. Compounds I and II formed by electrostatic attraction forces between counterions are stabilized by (NH₄⁺)NH...O(NO₃⁻) interionic hydrogen bonds.     

稀土配合物[Pr(C3H7NO2)2(C3H4N2)(H2O)](ClO4)3的标准生成焓及热分解动力学研究

合成了高氯酸镨和咪唑(C₃H₄N₂), DL-α-丙氨酸(C₃H₇NO₂)混配配合物晶体. 经傅立叶变换红外光谱、化学分析和元素分析确定其组成为[Pr(C₃H₇NO₂)₂(C₃H₄N₂)(H₂O)](ClO₄)₃. 使用具有恒温环境的溶解-反应量热计, 以2.0 mol•L^－1 HCl为量热溶剂, 在T＝(298.150±0.001) K时测定出化学反应PrCl₃•6H₂O(s)＋2C₃H₇NO₂(s)＋C₃H₄N₂(s)＋3NaClO₄(s)＝[Pr(C₃H₇NO₂)₂(C₃H₄N₂)(H₂O)](ClO₄)₃(s)＋3NaCl(s)＋5H₂O(1)的标准摩尔反应焓为Δ_rH_m^ө＝(39.26±0.11) kJ•mol^－1. 根据盖斯定律, 计算出配合物的标准摩尔生成焓为Δ_fH_m^ө{[Pr(C₃H₇NO₂)₂(C₃H₄N₂)(H₂O)](ClO₄)₃(s), 298.150 K}＝(－2424.2±3.3) kJ•mol^－1. 采用TG-DTG技术研究了配合物在流动高纯氮气(99.99%)气氛中的非等温热分解动力学, 运用微分法(Achar-Brindley-sharp和Kissinger法)和积分法(Satava-Sestak和Coats-Redfern法)对非等温动力学数据进行分析, 求得分解反应的表观活化能E＝108.9 kJ•mol^－1, 动力学方程式为dα/dt＝2(5.90×10⁸/3)(1－α)[－ln(1－α)]^－1exp(－108.9×10³/RT).     

离子交换-双氧水氧化法制备纳米CeO2晶体

以99.995% Ce(NO₃)₃和强碱性阴离子交换树脂为原料，采用离子交换-双氧水氧化法合成制备出纳米CeO₂晶体。并就离子交换反应中的Ce³⁺浓度、树脂加入速度和离子交换温度及H₂O₂加入速度等条件对CeO₂粒径的影响进行了探讨，得出了离子交换-双氧水氧化法制备纳米CeO₂晶体的最佳工艺条件。FTIR、TEM分析表明，离子交换法无需对合成的Ce(OH)₃溶胶进行洗涤即可去除NO₃^-、CO₃^2-等阴离子杂质，并用H₂O₂将该溶胶氧化，经真空干燥可制得粒径分布均匀，平均晶粒尺寸约3 nm，高纯度的CeO₂粉体。     

Conversion of NO in NO/N2, NO/O2/N2, NO/C2H4/N2 and NO/C2H4/O2/N2 Systems by Dielectric Barrier Discharge Plasmas

An experimental study on the conversion of NO in the NO/N₂, NO/O₂/N₂, NO/C₂H₄/N₂ and NO/C₂H₄/O₂/N₂ systems has been carried out using dielectric barrier discharge (DBD) plasmas at atmospheric pressure. In the NO/N₂ system, NO decomposition to N₂ and O₂ is the dominating reaction; NO conversion to NO₂ is less significant. O₂ produced from NO decomposition was detected by an on-line mass spectrometer. With the increase of NO initial concentration, the concentration of O₂ produced decreases at 298 K, but slightly increases at 523 K. In the NO/O₂/N₂ system, NO is mainly oxidized to NO₂, but NO conversion becomes very low at 523 K and over 1.6% of O₂. In the NO/C₂H₄/N₂ system, NO is reduced to N₂ with about the same NO conversion as that in the NO/N₂ system but without NO₂ formation. In the NO/C₂H₄/O₂/N₂ system, the oxidation of NO to NO₂ is dramatically promoted. At 523 K, with the increase of the energy density, NO conversion increases rapidly first, and then almost stabilizes at 93–91% of NO conversion with 61–55% of NO₂ selectivity in the energy density range of 317–550 J L⁻¹. It finally decreases gradually at high energy density. A negligible amount of N₂O is formed in the above four systems. Of the four systems studied, NO conversion and NO₂ selectivity of the NO/C₂H₄/O₂/N₂ system are the highest, and NO/O₂/C₂H₄/N₂ system has the lowest electrical energy consumption per NO molecule converted.     

Synthesis and structures of triphenylbismuth diaroxides Ph3Bi(OAr)2, Ar = C6H3(Br2-2,4), C6H2(Br2-2,6)(NO2-4), and C6H2[(NO2)3-2,4,6]

Triphenylbismuth diaroxides Ph₃Bi(OAr)₂ (Ar = C₆H₃(Br₂-2,4) (I), C₆H₂(Br₂-2,6)(NO₂-4) (II), and C₆H₂[(NO₂)₃-2,4,6] (III) are synthesized in yields up to 74% by the reaction of triphenylbismuth with phenols in the presence of hydrogen peroxide (taken at a molar ratio 1: 2: 1, respectively) in ether. According to X-ray diffraction data, the bismuth atoms in compounds I-III have distorted trigonal-bipyramidal coordination with the aroxyl substituents in the axial positions; the Bi-C, Bi-O bond lengths and the OBiO, CBiC angles vary in the intervals 2.162–2.204, 2.150–2.299 ? and 172.4°–176.1°, 109.6°–139.9°, respectively. Compound II exhibits intramolecular contacts between the central atom and ortho-Br atoms (3.924, 4.101 ?), and compound III has similar contacts of the Bi atom with the O atoms of the ortho-nitro groups (3.114, 3.313 ?). Original Russian Text ? V.V. Sharutin, I.V. Egorova, O.K. Sharutina, A.P. Pakusina, M.A. Pushilin, 2007, published in Koordinatsionnaya Khimiya, 2007, Vol. 33, No. 1, pp. 14–21.     

Crystal structure of [Pd(NH3)4][Rh(NH3)(NO2)5]

An XRD analysis is used to study the single crystal of [Pd(NH₃)₄][Rh(NH₃)(NO₂)₅] double complex salt at T = 150(2) K. Crystallographic characteristics are as follows: a = 7.6458(5) ?, b = 9.8813(6) ?, c = 9.5788(7) ?, β = 109.469(2)°, V = 682.30(8) ?³, P2₁/m space group, Z = 2, d _x = 2.553 g/cm³. The geometry of the complex [Rh(NH₃)(NO₂)₅]²⁻ anion is described for the first time: Rh-N(NO₂) distances are 2.020(4)–2.060(3) ?, Rh-N(NH₃) 2.074(4) ?, N(NO₂)-Rh-N(NH₃) trans-angle is 178.8(2)°.     

Acoustically oscillating emission from NO*2 produced by infrared photosensitized reaction in SF6 + NO2

An oscillating time profile was observed in the visible emission of NO^*₂ produced by an infrared photosensitized reaction in NO₂ + SF₆. The origin of the modulation was found to be the periodical heating of NO₂ due to the sound wave generated by the heat released from SF₆ upon infrared multiphoton excitation.     

Refinement of the (NH4)2Na[Rh(NO2)6] Crystal Structure

The crystal structure of (NH₄)₂Na[Rh(NO₂)₆] previously studied only from the data on polycrystals is refined. The selection of the Fm-3 space group is shown to be unambiguous. Geometrical characteristics of the complex [Rh(NO₂)₆]^3s-anion are: Rh—N 2.051 ?, N-O 1.237 ?, ∠O-N-O 119.0°.     

Synthesis, characterization and thermal properties of cobalt(II), nickel(II) and copper(II) complexes of 2,6-bis(3,4,5-trimethyl-N-pyrazolyl)pyridine): the crystal structure of [Co(btmpp)(H2O)2(NO3)]NO3

Co(II), Ni(II) and Cu(II) nitrate complexes with btmpp, namely ([Co(btmpp)(H₂O)₂(NO₃)]NO₃ (1), [Ni(btmpp)(H₂O)(NO₃)]NO₃ (2) and [Cu(btmpp)(MeOH)(NO₃)]NO₃ (3), where btmpp = 2,6-bis(3,4,5-trimethyl-N-pyrazolyl)pyridine), have been synthesized and characterized by physicochemical and spectroscopic methods. The crystal structure of complex 1 has been determined by single crystal diffraction at 100K. In all the complexes, btmpp is coordinated in a tridentate mode through its nitrogen atoms. One of the nitrates in complex 1 is terminally bonded to the metal center through the oxygen atom, whereas the other one is out of the coordination sphere. The Co(II) atom in complex 1 is hexa-coordinated with a CoN₃O₃ distorted octahedral environment. Decomposition of three complexes was analyzed thermogravimetrically. All three complexes decompose similar to explosive material.     

Messung von Stickoxiden im ppt-Bereich durch Chemiluminescenz mit O3

Zusammenfassung Ein hochempfindliches Gerät zum Nachweis von NO and NO₂ in der freien Atmosphäre wird vorgestellt. Das Meßprinzip ist Chemiluminescenz mit O₃. NO₂ wird durch einen vorgeschalteten Photolysekonverter in NO umgewandelt. Die Nachweisgrenze (2) beträgt bei einer Integrationszeit von 200 s ca. 5 ppt für NO und ca. 10 ppt für NO₂. Mögliche Interferenzen werden durch eine verbesserte Bestimmung des Nullpunkts erfaßt und korrigiert. Durch diese Prozedur werden innerhalb der Nachweisgrenze keine Querempfindlichkeiten mehr beobachtet. Die Eichung ist auf NBS-Standards zurückgeführt und stimmt innerhalb 10% mit unabhängigen Verfahren überein. Messungen des Vertikalprofils von NO und NO₂ in der Troposphäre demonstrieren die Leistungsfähigkeit des Geräts.

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Measurements of nitrogen oxides at ppt levels by chemiluminescence with O₃

Summary A sensitive chemiluminescent detector for the measurement of NO and NO₂ in the unpolluted atmosphere is described. For NO₂ measurement, a photolytic converter is employed. For a 200 s integration time, a detection limit (2) of 5 and 10 ppt is achieved for NO and NO₂, respectively. Interferences are measured and corrected by using a chemical zeroing procedure. Remaining interferences are below the detection limit. The calibration is based on NBS standards and agrees with independent techniques within 10%. Measurements of the vertical profile of NO and NO₂ in the troposphere exemplify the performance of the instrument.

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Herrn Prof. Dr. W. Fresenius zum 70. Geburtstag gewidmet     

Structure of [RuNO(NH3)3(H2O)Cl](NO3)2, product of interaction between hydroxonitrotriamminenitrosoruthenium(II) chloride and nitric acid

The structure of the product formed on boiling [RuNO(NH₃)₃(NO₂)(OH)]Cl·0.5H₂O in 3 M HNO₃ is determined by XRD. The crystals belong to monoclinic symmetry. Crystallographic data for H₁₁ClN₆O₈Ru are: a = 13.7924(4) ?, b = 6.9114(2) ?, c = 12.3577(4) ?, β = 111.863(1)°, V = 1093.27(6) ?³, Z = 4, d _calc = 2.185 g/cm³, space group Cc. The structure is built of complex [RuNO(NH₃)₃(H₂O)Cl]²⁺ cations and NO₃⁻ anions. The compound is studied by IR spectroscopy and X-ray phase analysis. Original Russian Text Copyright ? 2009 by V. A. Emel’yanov, E. V. Kabin, and I. A. Baidina __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 3, pp. 598–601, May–June, 2009.     

Layered structure of the silver coordination polymer with nonrigid aromatic diamine {Ag[CH2(C6H4NH2)2]2(CH3C6H4NH2)}NO3

The complex [Ag(DDM)₂(CH₃C₆H₄NH₂)]NO₃, where DDM is 4,4-diaminodiphenylmethane [CH₂(C₆H₄NH₂)₂], was synthesized and its structure was determined. The crystals are monoclinic, space group P2₁/n, a = 9.543(2) ?, b = 18.056(4) ?, c = 1.901(2) ?, β = 106.94(3)°, V = 1796.8(6) ?³, ρ_calcd = 1.443 g/cm³, Z = 4. The Ag atom (at the inversion center) is coordinated at the vertices of an almost undistorted octahedron by six nitrogen atoms of the primary amino groups from four bridging DDM molecules and two terminal p-toluidine molecules (Ag-N, 2.546(3) ?; NAgN, 89.7–90.3°). Wavelike layers composed of conjugate multiunit metal rings, each containing four Ag⁺ ions and four bridging DDM ligands, are formed in the structure in the [101] direction (a 2D polymer). Uncoordinated NO ₃ ⁻ anions are arranged in the cavities between the layers and link them by N-H⋯O hydrogen bonds. Original Russian Text ? Yu.V. Kokunov, V.V. Kovalev, Yu.E. Gorbunova, 2007, published in Zhurnal Neorganicheskoi Khimii, 2007, Vol. 52, No. 12, pp. 1992–1998.     

1-Allyl derivatives: Synthesis and crystal structures for [(NH2C5H4N(C3H5))2Cu3Cl3(NO3)2] and [C9H7N(C3H5)Cu(NO3)2]

1-Allyl-4-aminopyridinium chloride reacts with Cu(NO₃)₂ · 3H₂O in an ethanolic solution under the conditions of ac electrochemical synthesis at copper electrodes to form crystals of compound [(NH₂C₅H₄N(C₃H₅))₂Cu₃Cl₃(NO₃)₂] (I). The crystals of compound I are monoclinic: space group P2₁/c, Z = 4, a = 25.770(7), b = 7.230(4), c = 12.505(5) ?, β = 92.58(3)°, V = 2328(2) ?³. The direct interaction of 1-allylquinolinium nitrate with Cu(NO₃)₂ · 3H₂O in a methanolic solution in the presence of metallic copper yields crystals of compound [C₉H₇N(C₃H₅)Cu(NO₃)₂] (II). The crystals of compound II are triclinic: space group P , a = 6.756(3), b = 8.391(4), c = 12.489(5) ?, α = 77.18(3)°, β = 89.48(4)°, γ = 73.32(3)°, V = 662.0(5) ?³. The structure of compound I is built of infinite linear anions: polymeric fragments {(NH₂C₅H₄N(C₃H₅))₂Cu₃Cl₃(NO₃)₂} _n . Each of two copper atoms (Cu(1) and Cu(2)) π-coordinates the C=C bonds of the allyl groups of the 1-allyl-4-aminopyridinium cations, the oxygen atom of the nitrate ions, and two chlorine atoms. The third copper atom Cu(3) is linearly linked with two chlorine atoms. Particular polymeric fragments are additionally joined by the N-H…O, C-H…O, C-H…Cl hydrogen bonds. The crystal structure of compound II is built-up of the isolated L₂Cu₂(NO₃)₄ fragments (L is the 1-allylquinolinium cation). The metal atom is localized in the trigonal pyramidal coordination environment of three oxygen atoms of the nitrate ions and of the C=C bond of the allyl group of the cation. The particular L₂Cu₂(NO₃)₄ fragments are additionally joined by the C-H…O hydrogen bonds. Original Russian Text ? A.V. Pavlyuk, T. Lis, M.G. Mys’kiv, 2009, published in Koordinatsionnaya Khimiya, 2009, Vol. 35, No. 6, pp. 458–462.     

Etude de l’isotherme 25°C du système quasi quaternaire H2O-Zn(NO3)2·6H2O-Cu(NO3)2·3H2O-NH4NO3;I- Isoplèthes 4 masse% NH4NO3, 8 ma

The solid-liquid equilibria of the quasi-quaternary system H₂O-Zn(NO₃)₂·6H₂O-Cu(NO₃)₂·3H₂O-NH₄NO₃ were studied at 25°C by using a synthetic method based on conductivity measurements. Three isoplethic sections has been established at 25°C and the stable solid phases which appear are: NH₄NO₃(IV), Zn(NO₃)₂·6H₂O, anhydrous Cu(NO₃)₂, Cu(NO₃)₂·3H₂O and metastable Cu(NO₃)·2.5H₂O. Neither double salts, nor mixed crystals are observed at these temperatures and composition range.     

Kinetics of the reactions of isopropoxy radicals with NO,NO2, and O2

A fluorescence excitation spectrum of (CH₃)₂CHO (isopropoxy radical) is reported following photolysis of isopropyl nitrite at 355 nm. Rate constants for the reaction of isopropoxy with NO, NO₂, and O₂ have been measured as a function of pressure (1–50 Torr) and temperature (25–110°C) by monitoring isopropoxy radical concentrations using laser-induced fluorescence. We have obtained the following Arrhenius expressions for the reaction of isopropoxy with NO and O₂ respectively: (1.22±0.28)×10^?11 exp[(+0.62±0.14 kcal)/RT]cm²/s and (1.51±0.70)×10^?14 exp[(?0.39±0.28)kcal/RT]cm³/s where the uncertainties represent 2σ. The results with NO₂ are more complex, but indicate that reaction with NO₂ proceeds more rapidly than with NO contrary to previous reports. The pressure dependence of the thermal decomposition of the isopropoxy radical was studied at 104 and 133°C over a 300 Torr range using nitrogen as a buffer gas. The reaction is in the fall-off region over the entire range. Upper limits for the reaction of isopropoxy with acetaldehyde, isobutane, ethylene, and trimethyl ethylene are reported.We have performed the first LIF study of the isopropoxy radical. Arrhenius parameters were measured for the reaction of i-PrO with O₂, NO, NO₂, using direct radical measurement techniques. All reactions are in their high-pressure limits at a few Torr of pressure. The rate constant for the reactions of i-PrO with NO and NO₂ reactions exhibit a small negative activation energy. Studies of the i-PrO + NO₂ reaction produce data which indicate that O(³P) reacts rapidly with i-PrO. Unimolecular decomposition studies of i-PrO indicate that the reaction is in the fall-off region between 1 and 300 Torr of N₂ and the high-pressure limit is above 1 atmosphere of N₂.     

Catalytically Promoted NOx Sorption by ZrO2-Based Oxides

Metal promoted zirconia-based oxide sorbents, such as Pt–ZrO₂/Al₂O₃ for NO _x have been investigated. To clarify the role of the catalyst component, sorption of NO and NO₂ was compared using the samples with and without Pt. The catalytic oxidation of NO to NO₂ and successively to nitrate ions is an important role for the Pt catalyst. The experimental results indicate that a high-temperature calcination is essential to remove residual Cl from Pt–ZrO₂–Al₂O₃ prepared from H₂PtCl₆ in order to provide more active NO _x sorption sites. Of M–ZrO₂–Al₂O₃ samples investigated, ruthenium as well as Pt demonstrated relatively good performance as a catalyst component in the sorbent. The FT-IR spectra after sorption of NO and NO₂ demonstrated a strong band attributed to stored nitrate ions. The Pt catalyst was more resistant to sulfur poisoning than a base metal catalyst. However, the NO _x sorptive capacities of the Pt–ZrO₂/Al₂O₃ sorbents were expected to be deteriorated in dilute SO₂ as far as observed from FT-IR spectra.