Die Kristallstruktur der isotypen Verbindungen KAg(NO3)2, NH4Ag(NO3)2 und RbAg(NO3)2

KAg(NO₃)₂ crystallizes in space group P2₁/a-C _2h ⁵ ,a=13.953,b=4.955,c=8.220 Å, =97.76°,Z=4. X-ray intensities were collected with a two-circle diffractometer. The structure was solved by means of direct methods andFourier syntheses and was refined by the least squares method toR=0.034 with 1346 observed reflexions. ¹ {Ag₂(NO₃)₄}^2–-chains run parallel toy and are linked by potassium ions. Ag shows a distorted tetrahedral coordination with four relatively close O. K is irregularily surrounded by ten O. The isotypic compounds NH₄Ag(NO₃)₂ and RbAg(NO₃)₂ were refined toR=0.032 and 0.035, respectively. The coordination figures are compareable with those in KAg(NO₃)₂.

     

Synthesis and crystal structures of zirconium(IV) nitrate complexes (NO2)[Zr(NO3)3(H2O)3]2(NO3) 3, Cs[Zr(NO3)5], and (NH4)[Zr(NO3)5](HNO3)

The zirconium nitrate complexes (NO₂)[Zr(NO₃)₃(H₂O)₃]₂(NO₃)₃ (1), Cs[Zr(NO₃)₅] ((2), (NH₄)[Zr(NO₃)₅](HNO₃) (3), and (NO₂)_0.23(NO)_0.77[Zr(NO₃)₅] ((4) were prepared by crystallization from nitric acid solutions in the presence of H₂SO₄ or P₂O₅. The complexes were characterized by X-ray diffraction. The crystal structure of 1 consists of nitrate anions, nitronium cations, and [Zr(NO₃)₃(H₂O)₃]⁺ complex cations in which the Zr^IV atom is coordinated by three water molecules and three bidentate nitrate groups. The coordination polyhedron of the Zr^IV atom is a tricapped trigonal prism formed by nine oxygen atoms. The island structures of 2 and 3 contain [Zr(NO₃)₅]^? anions and Cs⁺ or NH₄ ⁺ cations, respectively. In addition, complex 3 contains HNO₃ molecules. Complex 4 differs from (NO₂)[Zr(NO₃)₅] in that three-fourth of the nitronium cations in 4 are replaced by nitrosonium cations NO⁺, resulting in a decrease in the unit cell parameters. In the [Zr(NO₃)₅]^? anion involved in complexes 2–4, the Zr^IV atom is coordinated by five bidentate nitrate groups and has an unusually high coordination number of 10. The coordination polyhedron is a bicapped square antiprism.     

Thermal Decomposition of CF3C(O)O2NO2, CClF2C(O)O2NO2, CCl2FC(O)O2NO2, and CCl3C(O)O2NO2

Haloacetyl, peroxynitrates are intermediates in the atmospheric degradation of a number of haloethanes. In this work, thermal decomposition rate constants of CF₃C(O)O₂NO₂, CClF₂C(O)O₂NO₂, CCl₂FC(O)O₂NO₂, and CCl₃C(O)O₂NO₂ have been determined in a temperature controlled 420 l reaction chamber. Peroxynitrates (RO₂NO₂) were prepared in situ by photolysis of RH/Cl₂/O₂/NO₂/N₂ mixtures (R = CF₃CO, CClF₂CO, CCl₂FCO, and CCl₃CO). Thermal decomposition was initiated by addition of NO, and relative RO₂NO₂ concentrations were measured as a function of time by long-path IR absorption using an FTIR spectrometer. First-order decomposition rate constants were determined at atmospheric pressure (M = N₂) as a function of temperature and, in the case of CF₃C(O)O₂NO₂ and CCl₃C(O)O₂NO₂, also as a function of total pressure. Extrapolation of the measured rate constants to the temperatures and pressures of the upper troposphere yields thermal lifetimes of several thousands of years for all of these peroxynitrates. Thus, the chloro(fluoro)acetyl peroxynitrates may play a role as temporary reservoirs of Cl, their lifetimes in the upper troposphere being limited by their (unknown) photolysis rates. Results on the thermal decomposition of CClF₂CH₂O₂NO₂ and CCl₂FCH₂O₂NO₂ are also reported, showing that the atmospheric lifetimes of these peroxynitrates are very short in the lower troposphere and increase to a maximum of several days close to the tropopause. The ratio of the rate constants for the reactions of CF₃C(O)O₂ radicals with NO₂ and NO was determined to be 0.64 ± 0.13 (2σ) at 315 K and a total pressure of 1000 mbar (M = N₂). © 1994 John Wiley & Sons, Inc.     

Die Ramanspektren der Jod(III)-nitrate CF3J(NO3)2, C6H5J(NO3)2 und J(NO3)3

Raman Spectra of the Iodine (III) Nitrates CF₃I(NO₃)₂, C₆H₅I(NO₃)₂, and I(NO₃)₃ The Raman spectra of the title compounds are recorded and discussed.     

Anhydrous Nitrates and Nitrosonium Nitratometallates of Manganese and Cobalt,M(NO3)2, NO[Mn(NO3)3], and (NO)2[Co(NO3)4]: Synthesis and Crystal Structure

Crystalline NO[Mn(NO₃)₃] ( I ) and (NO)₂[Co(NO₃)₄] ( II ) were synthesized by reaction of the corresponding metal and a liquid N₂O₄/ethylacetate mixture. I is orthorhombic, Pca2₁, a = 9.414(2), b = 15.929(3), c = 10.180(2) Å, Z = 4, R₁ = 0.0286. II is monoclinic, C2/c, a = 14.463(3), b = 19.154(4), c = 13.724(3) Å, β = 120.90(3), Z = 12, R₁ = 0.0890. Structure I consists of [Mn(NO₃)₃]^– sheets with NO⁺ cations between them. Two types of Mn atoms have CN_Mn = 7 and 8. Structure II is ionic containing isolated [Co(NO₃)₄]‐anions and NO⁺ cations with CN_Co = 8. Crystals of Mn(NO₃)₂ ( III ) and Co(NO₃)₂ ( IV ) were obtained by concentration of metal nitrate hydrate solutions in 100% HNO₃ in a desiccator with P₂O₅. III is cubic, Pa 3, a = 7.527(2) Å, Z = 4, R₁ = 0.0987. IV is trigonal, R 3, a = 10.500(2), c = 12.837(3) Å, Z = 12, R₁ = 0.0354. The three dimensional structure III is isotypic to the strontium and barium dinitrates. Structure IV contains a three dimensional network of interconnected Co(NO₃)_6/3 units with a distorted octahedral coordination environment of Co atoms. General correlations between central atom coordination and coordination modes of NO₃ groups are discussed.     

Uranyl dinitrate trihydrate,UO2(NO3)2(H2O)3

The structure of the title compound, which has been synthesized by evaporation at 294 K, consists of centrosymmetric uranyl hexagonal bipyramids that share opposite equatorial edges with two nitrate triangles, resulting in two distinct finite clusters of composition [(UO₂)(H₂O)₂(NO₃)₂]. There are two unique symmetrically independent U^VI positions and two unique nitrate groups.     

Neue Nitrosylkomplexe des Rheniums: ReCl3(NO)2, ReCl3(NO)2(CH3CN), AsPh4[ReCl4(NO)2]

New Nitrosyl Complexes of Rhenium: ReCl₃(NO)₂, ReCl₃(NO)₂(CH₃CN), AsPh₄[ReCl₄(NO)₂] ReCl₃(NO)₂, which is associated via chlorine bridges, was obtained in quantitative yield from rhenium pentachloride and trichloro nitromethane. Using acetonitrile, the monomer complex ReCl₃(NO)₂(CH₃CN) can be obtained from it, from which AsPh₄[ReCl₄(NO)₂] arises with tetraphenylarsoniumchloride. The i.r. spectra are reported and assigned. The crystal structures were determined for the latter two compounds with the help of X-ray diffraction data. ReCl₃(NO)₂(CH₃CN) crystallizes in the monoclinic space group P2₁/n with four molecules per unit cell, AsPh₄[ReCl₄(NO)₂] crystallizes in the tetragonal space group P4/n with two formula units. In all three compounds, the two NO groups linked to a Re atom are arranged cis to one another. As the anion in AsPh₄[ReCl₄(NO)₂] is situated on a fourfold axis, the cis-configuration causes a statistical disorder in the crystal.     

Calculations of chemical equilibria in Tb(NO3)3-H2O, Tb(NO3)3-heparin-H2O, and CaCl2-Tb(NO3)3-heparin-H2O systems in physiological saline solution

Chemical equilibria in the heterogeneous system Tb(NO₃)₃-H₂O, physiological saline solutions containing terbium nitrate, and unfractionated heparin ((H₄L) Tb(NO₃)₃-H₄L-H₂O-NaCl), and solutions containing calcium chloride, terbium nitrate, and unfractionated heparin (CaCl₂-Tb(NO₃)₃-H₄L-H₂O-NaCl) were studied by mathematical modeling and pH titration. A physicochemical model was designed for two-phase equilibria in the system Tb(NO₃)₃-H₂O, which consists of an aqueous solution and a solid phase of precipitated terbium hydroxide. Formation constants were calculated for terbium hydroxide ions Tb(OH) _i ^(3?i)+ (i = 1, 2, 3) in an aqueous phase, and a correlation was found between the amount of precipitated Tb(OH) ₃ ⁱ and pH. The four-component solution Tb(NO₃)₃-H₄L-H₂O-NaCl in the range 2.3 ≤ pH ≤ 10.4 is homogeneous; as a result of its investigation, the formation constants were ascertained for significant terbium complexes with heparin: TbL, TbHL ₂ ⁴ , and Tb(OH)₂L^3?. Chemical equilibria in the five-component solution CaCl₂-Tb(NO₃)₃-H₄L-H₂O-NaCl were modeled proceeding from the models developed for equilibria in the four-component solution subsystems Tb(NO₃)₃-H₄L-H₂O-NaCl and CaCl₂-H₄L-H₂O-NaCl. The modeling showed that the Tb³⁺ ion is an efficient competitive complex former to the Ca²⁺ ion, which forms complexes with heparin, and decreases tenfold the concentration of the major complex NaCaL at 6.8 ≤ pH ≤ 7.4 (the pH range of blood plasma stability).     

Mercurous Dimethylglyoximato Nitrate,Hg2(Dmg)2(NO3)2

Colourless needles of mercurous dimethylglyoximato nitrate, Hg₂(Dmg)₂(NO₃)₂, grow from a diluted nitric acid solution of mercurous nitrate and dimethylglyoxime. The crystal structure (triclinic, P1¯, a = 728.50(13), b = 1066.8(2), c = 1167.9(2) pm, α = 93.78(2)°, β = 94.16(2)°, γ = 98.61(2)°, R_all = 0, 0726) contains the cations [Hg₂(Dmg)₂]²⁺ and “non‐coordinating” (NO₃)^— anions. In the cation, two neutral dimethylglyoxime molecules coordinate bidentately with Hg—N distances in the narrow range of 236 to 239 pm to the mercurous ion, Hg₂²⁺, which exhibits a Hg—Hg bond distance of 252.23(8) pm).     

Diffusion of Aqueous Solutions of CoCl2, Co(NO3)2, and Cu(NO3)2 in Porous Glass Membranes

Diffusion coefficients of CoCl₂, Co(NO₃)₂, and Cu(NO₃)₂ salts, characterizing permeation of their aqueous solutions across glass membranes with predominant pore radius in the range from 70 to 4.5 nm are determined. With pores in the membranes becoming narrower, the diffusion mobility of the electrolytes decreases.     

Interactions in the Quinary System H2O-Y(NO3)3-La(NO3)3-Pr(NO3)3-Nd(NO3)3 to Very High Concentrations

Isopiestic measurements have been carried out for the quinary system H₂O-Y(NO₃)₃-La(NO₃)₃-Pr(NO₃)₃-Nd(NO₃)₃ at 298.15 K to near saturation. The measurements can be represented within experimental uncertainty over the full concentration range by a modified Pitzer ion-interaction model extending to the C ⁽³⁾ term. In addition, the system obeys the Zdanovskii–Stokes–Robinson model or partial ideal solution model within the accuracy of the isopiestic measurements, indicating zero interchange energy between the unlike salts, which is consistent with the nature of trivalent rare-earth elements.     

A single crystal ESR study of Gd(bipy)2(NO3)3 in La(bipy)2(NO3)3

The single crystal ESR spectrum of Gd³⁺ doped into La(bipy)₂(NO₃)₃ has been recorded at 290 K for many orientations of the crystal axes with respect to the magnetic field. A good fit of the spin Hamiltonian parameters to the experimental data has been achieved with a more efficient algorithm than previously used in this context, a significant saving being the computation of the eigenvalues only. It has been shown that previously reported spin Hamiltonian parameters for the title compound are not sufficient to describe the spectra recorded for arbitrary orientations of the single crystal and that low symmetry Gd³⁺ complexes require all possible parameters to be included.     

Solubility products of basic salts Cu2(OH)3NO3 and Hg3O2(NO3)2, determined from dilatometric data

The solubility products of basic salts Cu₂(OH)₃NO₃ and Hg₃O₂(NO₃)₂ were determined using dilatometric data.