双腔热解光腔衰荡光谱仪测量大气中NO2和RNO2

A two-channel thermal dissociation cavity ring down spectroscopy (CRDS) instrument has been built for in situ, real-time measurement of NO₂ and total RNO₂ (peroxy nitrates and alkyl nitrates) in ambient air, with a NO₂ detection limit of 0.10 ppbv at 1 s. A 6-day long measurement was conducted at urban site of Hefei by using the CRDS instrument with a time resolution of 3 s. A commercial molybdenum converted chemiluminescence (Mo-CL) instrument was also used for comparison. The average RNO₂ concentration in the 6 days was measured to be 1.94 ppbv. The Mo-CL instrument overestimated the NO₂ concentration by a bias of +1.69 ppbv in average, for the reason that it cannot distinguish RNO₂ from NO₂. The relative bias could be over 100% during the afternoon hours when NO₂ was low but RNO₂ was high.     

Preparation and mechanism of thermal decomposition of solid complexes of RE(NO3)3(Sm,Tb) with aspartic acid

Journal of Thermal Analysis and Calorimetry - Solid complexes of RE(NO3)3(Sm, Tb) and aspartic acid were prepared for the first time in aqueous solution. Based on chemical analysis, elemental...     

Thermodynamic properties and solution equilibria of aqueous bivalent transition metal nitrates and magnesium nitrate

Osmotic coefficients for Mn(NO₃)₂, Co(NO₃)₂, Ni(NO₃)₂, Cu(NO₃)₂, Zn(NO₃)₂, and Mg(NO₃)₂ in aqueous solution have been determined by the isopiestic method at 25°C, and activity coefficients have been derived. The results agree with the literature data for Zn(NO₃)₂, while they are significantly different for Co(NO₃)₂, Cu(NO₃)₂, and Mg(NO₃)₂, and those for Mn(NO₃)₂ and Ni(NO₃)₂ are new. The concentration dependence of the osmotic coefficients for the bivalent metal nitrates is similar to that for the trifluoroacetates, while it differs from those for the other salts of the same series of metals. The results are discussed in terms of the inner-sphere and outer-sphere association of ions, auxiliary information being derived from the concentration effects in the visible spectra of the coloured metal nitrates.     

Determination of Total Selenium in Human Urine and Serum by Graphite-Furnace Atomic-Absorption Spectrophotometry with Palladium-Nickel-Ammonium Nitrates as a Matrix Modifier

After human urine or serum was diluted (1 + 9) with HNO₃ (0.2%, v/v) and standard additions of Se solution (100 μ L^?1), the diluted sample (10 μL) was introduced into the graphite cuvette. The matrix modifier [10μL, containing Pd (0.6 μg) + Ni (25 μg) + NH₄NO₃ (80 μg) in HNO₃ (0.2%, v/v) for urine, or Pd (0.3 μg) + Ni (30 μg) + NH₄NO₃ (80 μg) + Triton X-100 (0.04%) in HNO₃ (0.2%, v/v) for serum, respectively] was added and the mixture was heated according to a temperature program. The matrix modifier containing NH₄NO₃ in a suitable amount and a small amount of Pd enhanced the sensitivity for Se. The method detection limits (3σ) after dilution were about 4.9 ± 0.8 and 2.36 ± 0.18 μg L^?1 for urine and serum, respectively. The accuracy of this method was tested with SRM #2670 human urine Se and Seronorm Trace Elements #116 human serum Se, respectively, and the results of 97.6 – 101% and 100 – 104% were obtained with precision ± 0.3% and ± 2%, respectively. This method can be applied easily and accurately to the determination of concentration of total Se in human urine and serum.     

Modeling of Aqueous 3–1 Rare Earth Electrolytes and Their Mixtures to Very High Concentrations

A simple modification to the Pitzer ion–interaction model has been presented for osmotic and activity coefficients of aqueous solutions of highly soluble and highly unsymmetrical electrolytes and their mixtures. The equations extending to the C⁽³⁾ parameter enable the literature osmotic and activity coefficients of aqueous rare earth nitrates, perchlorates and chlorides at 298.15 K to be represented accurately from infinite dilution to maximum saturation or supersaturation concentrations available. The ionic interactions have also been investigated from the isopiestic measurements on aqueous mixtures Y(NO₃)₃–La(NO₃)₃, Y(NO₃)₃–Pr(NO₃)₃, Y(NO₃)₃–Nd(NO₃)₃, La(NO₃)₃–Pr(NO₃)₃, La(NO₃)₃–Nd(NO₃)₃ and Pr(NO₃)₃–Nd(NO₃)₃ at 298.15 K to near saturation, and the simple modification can represent the new measurements within experimental uncertainty over the full concentration range. In addition, the Zdanovskii-Stokes-Robinson model or partial ideal solution model is obeyed by all the mixtures within isopiestic accuracy, which is consistent with the nature of rare earth elements.     

Bismuth(III) salts mediated regioselective ring opening of epoxides: an easy route to halohydrins and β-hydroxy nitrates

The ring opening of various epoxides was achieved under mild conditions using bismuth(III) salts. Halohydrins and β-hydroxy nitrates were efficiently obtained from the corresponding 5α,6α-, 2α,3α-, and 5β,6β-epoxysteroid using BiCl₃, BiBr₃ or Bi(NO₃)₃·5H₂O. Considerations about the probable reaction mechanism are provided. 2D homo- and heteronuclear correlation NMR spectroscopic techniques were used to unequivocally demonstrate the trans-diaxial nature of the epoxide ring opening.     

芳香胺及其氮氧化物合希土配合物的研究 V.2, 2''—联喹啉—N, N''—二氧化物合硝酸希土固体配合物的合成及其性质

在无水乙醇和氯仿混合溶剂中使重希土硝酸盐与2,2′—联喹啉—N,N′—二氧化物(BiqO_2)作用,制得了固体配合物Ln(BiqO_2)(NO_3)_3·2H_2O(Ln=Tm,Yb,Lu,Y)。通过元素分析、X光粉末衍射物相分析、差热—热重分析、红外光谱、紫外光谱、溶解性及摩尔电导测定,研究了配合物的组成及其有关性质。     

Synthese,Struktur und Thermolyse der ternären Ammoniumnitrate (NH4)3[M2(NO3)(9] (M  La?Gd)

Synthesis, Structure, and Thermolysis of the (NH₄)₃[M₂(NO₃)₉] (M ? La? Gd) The ternary ammonium nitrates (NH₄)₃[M₂(NO₃)₉] (M ? La-Gd) are obtained as single crystals from a solution of the respective sesquioxides in a melt of NH₄NO₃ and sublimation of the excess NH₄NO₃. In the crystal structure of (NH₄)₃[Pr₂(NO₃)₉] (cubic, P4₃32, Z = 4, a = 1 377.0(1) pm, R = 0.038, R_w = 0.023) Pr³⁺ is surrounded by six bidentate nitrate ligands of which three are bridging to neighbouring Pr³⁺ ions. This results in a branched folded chain, held together by the NH₄⁺ ions which occupy cavities in the structure. (NH₄)₃[Pr₂(NO₃)₉] is the first intermediate product of the thermal decomposition of (NH₄)₂[Pr(NO₃)₅(H₂O)₂] · 2H₂O.     

新氮杂冠醚稀土配合物的制备、表征及其荧光性质

合成了一新的大环氮杂冠醚及其稀土配合物,并通过元素分析、摩尔电导、热分析及红外的测定对配合物进行了表征。结果表明,冠醚配体上的C和N原子均参与配位,并推测了配合物的可能组成。室温下研究了配合物的固体及在溶液中的荧光光谱。固态时Sm^3 ,Eu^3 ,TB^3 ,Dy^3 的冠醚配合物均有较强荧光,其中Tb^3 的荧光强度最高,表明冠醚配体三重态的能量与Tb^3 的振动能级更为匹配。在Eu^3 配合物中,强度比η(^5D0→^7F2/^5D0→^7F1)=5.3,表明Eu^3 处于一非对称配位环境中。     

Rare‐Earth Oxide Nanostructures: Rules of Rare‐Earth Nitrate Thermolysis in Octadecylamine

The decomposed regularity of rare‐earth nitrates in octadecylamine (ODA) is discussed. The experimental results show that these nitrates can be divided into four types. For rare‐earth nitrates with larger RE³⁺ ions (RE=rare earth, La, Pr, Nd, Sm, Eu, Gd), the decomposed products exhibited platelike nanostructures. For those with smaller RE³⁺ ions (RE=Y, Dy, Ho, Er, Tm, Yb), the decomposed products exhibited beltlike nanostructures. For terbium nitrate with a middle RE³⁺ ion, the decomposed product exhibited a rodlike nanostructure. The corresponding rare‐earth oxides, with the same morphologies as their precursors, could be obtained when these decomposed products were calcined. For cerium nitrate, which showed the greatest differences, flowerlike cerium oxide could be obtained directly from decomposition of the nitrate without further calcination. This regularity is explained on the basis of the lanthanide contraction. Owing to their differences in electron configuration, ionic radius, and crystal structure, such a nitrate family therefore shows different thermolysis properties. In addition, the potential application of these as‐obtained rare‐earth oxides as catalysts and luminescent materials was investigated. The advantages of this method for rare‐earth oxides includes simplicity, high yield, low cost, and ease of scale‐up, which are of great importance for their industrial applications.