Ga2O3-La2O3-Yb2O3-Er2O3(HO2O3)体系光谱性质的研究

根据稀土离子能级的特点,对Ga2O3-La2O3-Yb2O3-Er2O3(HO2O3)体系的光谱性质进行了探讨,发现它们有二类发光性质:Stokes发光和反Stokes发光,研究了发光强度和发射波长与掺杂离子的依赖关系,观察到由能量的共振转移引起的荧光浓度猝灭现象,并取得了最大发光强度时的掺杂离子浓度和一些规律性结果.     

Methanesulfonates of high-valent metals: syntheses and structural features of MoO2(CH3SO3)2, UO2(CH3SO3)2, ReO3(CH3SO3), VO(CH3SO3)2, and V2O3(CH3SO3)4 and their thermal decomposition under N2 and O2 atmosphere

Oxide methanesulfonates of Mo, U, Re, and V have been prepared by reaction of MoO(3), UO(2)(CH(3)COO)(2)·2H(2)O, Re(2)O(7)(H(2)O)(2), and V(2)O(5) with CH(3)SO(3)H or mixtures thereof with its anhydride. These compounds are the first examples of solvent-free oxide methanesulfonates of these elements. MoO(2)(CH(3)SO(3))(2) (Pbca, a=1487.05(4), b=752.55(2), c=1549.61(5) pm, V=1.73414(9) nm(3), Z=8) contains [MoO(2)] moieties connected by [CH(3)SO(3)] ions to form layers parallel to (100). UO(2)(CH(3)SO(3))(2) (P2(1)/c, a=1320.4(1), b=1014.41(6), c=1533.7(1) pm, β=112.80(1)°, V=1.8937(3) nm(3), Z=8) consists of linear UO(2)(2+) ions coordinated by five [CH(3)SO(3)] ions, forming a layer structure. VO(CH(3)SO(3))(2) (P2(1)/c, a=1136.5(1), b=869.87(7), c=915.5(1) pm, β=113.66(1)°, V=0.8290(2) nm(3), Z=4) contains [VO] units connected by methanesulfonate anions to form corrugated layers parallel to (100). In ReO(3)(CH(3)SO(3)) (P1, a=574.0(1), b=1279.6(3), c=1641.9(3) pm, α=102.08(2), β=96.11(2), γ=99.04(2)°, V=1.1523(4) nm(3), Z=8) a chain structure exhibiting infinite O-[ReO(2)]-O-[ReO(2)]-O chains is formed. Each [ReO(2)]-O-[ReO(2)] unit is coordinated by two bidentate [CH(3)SO(3)] ions. V(2)O(3)(CH(3)SO(3))(4) (I2/a, a=1645.2(3), b=583.1(1), c=1670.2(3) pm, β=102.58(3), V=1.5637(5) pm(3), Z=4) adopts a chain structure, too, but contains discrete [VO]-O-[VO] moieties, each coordinated by two bidentate [CH(3)SO(3)] ligands. Additional methanesulfonate ions connect the [V(2)O(3)] groups along [001]. Thermal decomposition of the compounds was monitored under N(2) and O(2) atmosphere by thermogravimetric/differential thermal analysis and XRD measurements. Under N(2) the decomposition proceeds with reduction of the metal leading to the oxides MoO(2), U(3)O(7), V(4)O(7), and VO(2); for MoO(2)(CH(3)SO(3))(2), a small amount of MoS(2) is formed. If the thermal decomposition is carried out in a atmosphere of O(2) the oxides MoO(3) and V(2)O(5) are formed.     

2-Formyl-3-Methoxymethylindole, 3-Ethoxymethyl-2-Formylindole and 2-Formyl-3-Methylindole

Base-catalysed hydrolysis of 2-formyl-3-methyl-1-phenyl-sulphonylindole results in the formation of 3-alkoxy-methyl-2-formylindoles. Cleavage of the 1-phenyl-sulphonyl group with sodium amalgam produces 2-hydroxymethyl-3-methylindole.     

Reciprocal system 3Tl2S + Bi2Se3 ↔ 3Tl2Se + Bi2S3

The reciprocal system 3Tl₂S + Bi₂Se₃ ? 3Tl₂Se + Bi₂S₃ has been investigated by DTA, X-ray powder diffraction analysis, and emf measurements. Some polythermal sections and the isothermal section at 500 K of the phase diagram and the projection of the liquidus surface of this system have been constructed, and the types and coordinates of the invariant and univariant equilibria have been determined. The existence of wide regions of quaternary solid solutions based on the binary compounds Tl₂S, Tl₂Se, Bi₂S₃, and Bi₂Se₃, and solid solutions between the temary compounds TlBiS₂ and TlBiSe₂ have been established.     

Secondary kinetics of methanol decomposition: theoretical rate coefficients for 3CH2 + OH, 3CH2 + 3CH2, and 3CH2 + CH3

Direct variable reaction coordinate transition state theory (VRC-TST) rate coefficients are reported for the (3)CH(2) + OH, (3)CH(2) + (3)CH(2), and (3)CH(2) + CH(3) barrierless association reactions. The predicted rate coefficient for the (3)CH(2) + OH reaction (approximately 1.2 x 10(-10) cm(3) molecule(-1) s(-1) for 300-2500 K) is 4-5 times larger than previous estimates, indicating that this reaction may be an important sink for OH in many combustion systems. The predicted rate coefficients for the (3)CH(2) + CH(3) and (3)CH(2) + (3)CH(2) reactions are found to be in good agreement with the range of available experimental measurements. Product branching in the self-reaction of methylene is discussed, and the C(2)H(2) + 2H and C(2)H(2) + H2 products are predicted in a ratio of 4:1. The effect of the present set of rate coefficients on modeling the secondary kinetics of methanol decomposition is briefly considered. Finally, the present set of rate coefficients, along with previous VRC-TST determinations of the rate coefficients for the self-reactions of CH(3) and OH and for the CH(3) + OH reaction, are used to test the geometric mean rule for the CH(3), (3)CH(2), and OH fragments. The geometric mean rule is found to predict the cross-combination rate coefficients for the (3)CH(2) + OH and (3)CH(2) + CH(3) reactions to better than 20%, with a larger (up to 50%) error for the CH(3) + OH reaction.     

Al2O3-B2O3-Eu2O3体系的振动光谱和发光特性

采用高温固相反应法,合成了一系列不同组份的磷光体,测定了它们的振动光谱．结果表明,随着Al／B比的减小,在1100～1000cm－1的区域内的振动光谱没有明显变化,铕离子不可能进入Al18B4O33的晶格中;振动光谱的背底升高,非晶相逐渐增加．研究了Al2O3－B2O3-Eu2O3中Eu3＋离子的光谱特性,发现随着Al／B比的减少,Eu3＋离子的存在相由晶相逐渐向非晶相转化。在非晶相中,Eu3＋离子的声子伴带表明电子与声子的耦合强度随着Al／B比的减少而减小,Eu3＋离子的发射强度相应的增加,这与多声子弛豫的理论一致．     

2MgO·2B_2O_3·MgCl_2·14H_2O-H_3BO_3-H_2O体系30℃相平衡

用相平衡方法研究了2MgO·2B_2O_3·MgCl_2·14H_2O-H_3BO_3-H_2O在30 ℃ 不同浓度H_3BO_3水溶液中的溶解转化产物及其溶解度。结果表明，氯柱硼镁石的 溶解转化产物，在H_3BO_3质量分数≤2.50%时为多水硼镁石；在2.50% ～ 5. 00%H_3BO_3范围时为库水硼镁石；当H_3BO_3量在5.00% ～ 5.60%之间时为章氏硼 镁石；而当H_3BO_3量≥5.60%时为三方硼镁石。提出了溶解相转化机理。     

还原态WO_3/Al_2O_3,NiO/Al_2O_3和NiO-WO_3/Al_2O_3催化剂上H_2,CO,O_2的吸附特性

在加氢精制和许多其它催化过程中,Mo,W是主要的活性组分,Co,Ni通常作为助剂,有关Co-Mo体系的研究文献报导很多~[1.2], 但由于钨较难还原和硫化,关于     

Vibrational analysis of Ag3(PO2NH)3, Na3(PO2NH)3 x H2O, Na3(PO2NH)3 x 4H2O,

FT IR and FT Raman spectra of Ag3(PO2NH), (Compound 1), Na3(PO2NH)3 x H2O (Compound II), Na3(PO2NH)3 x 4H2O (Compound III), [C(NH2)3]3(PO2NH)3 x H2O (Compound IV) and (NH4)4(PO2NH)4 x 4H2O (Compound V) are recorded and analyzed on the basis of the anions, cations and water molecules present in each of them. The PO2NH- anion ring in compound I is distorted due to the influence of Ag+ cation. Wide variation in the hydrogen bond lengths in compound III is indicated by the splitting of the v2 and v3 modes of vibration of water molecules. The NH4 ion in compound V occupies lower site symmetry and exhibits hindered rotation in the lattice. The correlations between the symmetric and asymmetric stretching vibrations of P-N-P bridge and the P-N-P bond angle have also been discussed.     

PbCu3(OH)(NO3)(SeO3)3·1/2H2O und Pb2Cu3O2(NO3)2(SeO3)2: Synthese und Kristallstrukturuntersuchung

Crystals of PbCu₃(OH)(NO₃)(SeO₃)₃·1/2H₂O [a=7.761(3)Å,b=9.478(4)Å,c=9.514(4)Å, =66.94(2)°, =69.83(2)°, =81.83(2)°, space group P ,Z=2] and Pb₂Cu₃O₂(NO₃)₂(SeO₃)₂ [a=5.884(2)Å,b=12.186(3)Å,c=19.371(4)Å, space group Cmc2₁,Z=4] were synthesized under hydrothermal conditions. Their crystal structures were refined with three-dimensional X-ray data toR _w=0.033 resp. 0.055. In PbCu₃(OH)(NO₃)(SeO₃)₃·1/2H₂O the Cu atoms are [4+1] and [4+2] coordinated and via SeO₃ groups a three-dimensional atomic arrangement is built up. In Pb₂Cu₃O₂(NO₃)₂(SeO₃)₂ there are sheets, which are connected only via Pb-O bonds ranging from 2.98 Å to 3.16 Å.

     

Kinetics of gas‐phase reactions of CH3OCH2CF3, CH3OCH3, CH3OCH2CH3, CH3CH2OCH2CH3, and CHF2CF2OCH2CF3 with NO3 radicals at 298 K

Rate constants for the gas‐phase reactions of CH₃OCH₂CF₃ (k₁), CH₃OCH₃ (k₂), CH₃OCH₂CH₃ (k₃), and CH₃CH₂OCH₂CH₃ (k₄) with NO₃ radicals were determined by means of a relative rate method at 298 K. NO₃ radicals were prepared by thermal decomposition of N₂O₅ in a 700–750 Torr N₂O₅/NO₂/NO₃/air gas mixture in a 1‐m³ temperature‐controlled chamber. The measured rate constants at 298 K were k₁ = (5.3 ± 0.9) × 10^?18, k₂ = (1.07 ± 0.10) × 10^?16, k₃ = (7.81 ± 0.36) × 10^?16, and k₄ = (2.80 ± 0.10) × 10^?15 cm³ molecule^?1 s^?1. Potential energy surfaces for the NO₃ radical reactions were computationally explored, and the rate constants of k₁–k₅ were calculated according to the transition state theory. The calculated values of rate constants k₁–k₄ were in reasonable agreement with the experimentally determined values. The calculated value of k₅ was compared with the estimate (k₅ < 5.3 × 10^?21 cm³ molecule^?1 s^?1) derived from the correlation between the rate constants for reactions with NO₃ radicals (k₁–k₄) and the corresponding rate constants for reactions with OH radicals. We estimated the tropospheric lifetimes of CH₃OCH₂CF₃ and CHF₂CF₂OCH₂CF₃ to be 240 and >2.4 × 10⁵ years, respectively, with respect to reaction with NO₃ radicals. The tropospheric lifetimes of these compounds are much shorter with respect to the OH reaction. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 490–497, 2009     

Synthesis and characterization of the open-framework barium bisphosphonate [Ba3(O3PCH2NH2CH2PO3)2(H2O)4].3H2O

Following the strategy of using polyfunctional phosphonic acids for the synthesis of open-framework metal phosphonates, the phosphonocarboxylic acid (H2O3PCH2)2NCH2C6H4COOH was used in the hydrothermal synthesis of new Ba phosphonates. Its decomposition led to the first open-framework barium phosphonate [Ba3(O3PCH2NH2CH2PO3)2(H2O)4].3H2O. The synthesis was also successfully performed using iminobis(methylphosphonic acid), (H2O3PCH2)2NH, as a starting material, and the synthesis was optimized to obtain as a pure material. The reaction setup as well as the pH are the dominant parameters, and only a diffusion-controlled reaction led to the desired compound. The crystal structure was solved from single-crystal data: monoclinic; C2/c; a=2328.7(2), b=1359.95(7), and c=718.62(6) pm; beta=98.732(10) degrees ; V=2249.5(3)x10(6) pm3; Z=4; R1=0.036; and wR2=0.072 (all data). The structure of [Ba3(O3PCH2NH2CH2PO3)2(H2O)4].3H2O is built up from BaO8 and BaO10 polyhedra forming BaO chains and layers, respectively. These are connected to a three-dimensional metal-oxygen-metal framework with the iminobis(methylphosphonic acid) formally coating the inner walls of the pores. The one-dimensional pores (3.6x4 A) are filled with H2O molecules that can be thermally removed. Thermogravimetric investigations and temperature-dependent X-ray powder diffraction demonstrate the stability of the crystal structure up to 240 degrees C. The uptake of N,N-dimethylformamide and H2O by dehydrated samples is demonstrated. Furthermore, IR, Raman, and 31P magic-angle-spinning NMR data are also presented.     

2MgO·2B2O3·MgCl2·14H2O-7.8%H3BO3-H2O体系多温相关系研究

研究了2MgO·2B2O3·MgCl2·14H20在不同温度下的7.8%H3BO3水溶液中的相转化产物及其溶解度.IR,XRD,TG及化学分析表明,相转化产物在0～22℃范围内为MgO·2B2O3·9H20;22～68℃为MgO·2B2O3·7.5H20;68～95℃为MgO·2B2O3·7H20;95～98.8℃为MgO·2B2O3·5H20;100～110℃为MgO·B2O3·3H20;110～120℃为2MgO·B2O3·2H20;120～170℃为2MgO·B2O3·1.5H20;170～200℃为2MgO·B2O3·H20.提出了相转化反应原理.     

Darstellung und Kristallstruktur der Dialkalimetalltrichalkogenide Rb2S3, Rb2Se3, Cs2S3 und Cs2Se3

Preparation and Crystal Structure of the Dialkali Metal Trichalcogenides Rb₂S₃, Rb₂Se₃, Cs₂S₃, and Cs₂Se₃ Crystalline products were obtained by the reaction of the pure alkali metals with the chalcogens in the molar ratio 2:3 in liquid ammonia at pressures up to 3000 bar and temperatures around 600 K. The substances crystallize in the K₂S₃ type structure (space group Cmc2₁(NO. 36)). Unit cell constants see ?Inhaltsübersicht”?. The characteristic feature of this structure are bent polyanions X₃^2?:(X = S,Se). The new described compounds are compared with the other known alkali metal trichalcogenides.     

A photoelectron photoion coincidence study of the vinyl bromide and tribromoethane ion dissociation dynamics: heats of formation of C2H3+, C2H3Br, C2H3Br+, C2H3Br2+, and C2H3Br3

The threshold photoelectron photoion coincidence (TPEPICO) technique has been used to measure accurate dissociative photoionization onsets of vinyl bromide and 1,1,2-tribromoethane. The reactions investigated and their 0 K onsets are C2H3Br + hnu --> C2H3+ + Br (11.902 +/- 0.008 eV); C2H3Br3 + hnu --> C2H3Br2+ + Br (10.608 +/- 0.008 eV); and (C2H3Br3 + hnu --> C2H3Br+ + 2Br (12.301 +/- 0.035 eV). The vinyl ion heat of formation (Delta(f)H degrees 298K = 1116.1 +/- 3.0 kJ/mol) has been calculated using W1 theory and used as an anchor along with the measured dissociation energies to determine the heats of formation, Delta(f)H degrees 298K, in kJ/mol, of the following bromine-containing species: C2H3Br (74.1 +/- 3.1), C2H3Br+ (1021.9 +/- 3.1), C2H3Br2+ (967.1 +/- 4.0), and C2H3Br3 (53.5 +/- 4.3). These results represent accurate and consistent experimental determinations of heats of formation for these bromine-containing species, which serve to correct the discrepancies in the literature for C2H3Br and C2H3Br+ and provide the first experimental determination for the enthalpies of formation of C2H3Br2+ and C2H3Br3.     

Die Kristallstruktur von Cs2PrO3, sowie über Cs2CeO3, Cs2TbO3, Rb2CeO3 und Rb2TbO3

Crystal Structure of Cs₂PrO₃ and also about Cs₂CeO₃, Cs₂TbO₃, Rb₂CeO₃, and Rb₂TbO₃ New prepared Cs₂PrO₃ (dark brown) is orthorhombic due to single crystal data, K₂PbO₃ type of structure (Cmc2₁) with a = 11.4₇, b = 7.72₂, c = 6.42₇ Å and Z = (4). Cs₂CeO₃ (colourless, a = 11.49₅, b = 7.75₃, c = 6.43₇ Å), Cs₂TbO₃ (red-brown, a = 11.3₇, b = 7.72₆, c = 6.14₂ Å), and the low-temperature form of (LT-) Rb₂TbO₃ (red-brown, a = 10.9₁, b = 7.39₀, c = 6.09₉ Å) are isotypic. Hitherto unknown HT-Rb₂CeO₃ (high-temperature form, colourless, a = 3.83₇, c = 18.4₇ Å, Z = 2, hexagonal) and “HT-Rb₂TbO₃” (red-brown, a = 3.77₃, c = 18.0₀ Å) correspond according to powder-data to the α-NaFeO₂ type of structure. Cs₂PrO₃ has been measured magnetically (100–300 K). The Madelung Part of Lattice Energy (MAPLE) is calculated and discussed.     

Eu3+掺杂Y2O3-Al2O3-SiO2玻璃的制备与荧光性能研究

采用高温熔融法制备了Eu³⁺掺杂Y₂O₃-Al₂O₃-SiO₂荧光玻璃,探讨了成分对该体系玻璃形成能力的影响,并对不同Eu³⁺掺杂浓度下的荧光性能进行了研究.结果表明,熔融温度为1500℃条件下,SiO₂含量对该体系的玻璃形成能力影响明显,Y/Al摩尔比为3/5时,SiO₂含量在52%-68%(摩尔分数)范围内时可以获得玻璃.掺杂Eu³⁺的Y₂O₃-Al₂O₃-SiO₂玻璃具有荧光性能,在395nm波长激发下,在588 nm和614 nm处出现明显的发射峰.随着Eu³⁺掺杂浓度的增加,该荧光玻璃的发射波长不变,但发射强度有所变化;当Eu³⁺掺杂浓度为1.5%(摩尔分数)时,特征发射峰强度最大.     

NiO-La_2O_3-Al_2O_3气凝胶催化剂的制备

采用改进的溶胶 -凝胶法和超临界干燥技术制备出超细三元 Ni O- L a2 O3 - Al2 O3 气凝胶催化剂 .通过 BET、TEM、XRD、DTA、IR等物性表征 ,考察了煅烧温度和组成等对气凝胶催化剂制备的影响 .结果表明 ,此种方法制备的多元气凝胶催化剂不仅保留了氧化铝和 Ni O- Al2 O3 气凝胶的主要特征 ,而且 ,氧化镧的加入使气凝胶更易晶化 ,热稳定性更好和吸附能力更强 .这种改进的溶胶 -凝胶法和超临界干燥技术操作简单有效 ,适合要求组分之间相互作用强、分布均匀、结构热稳定性好的多组元负载催化剂的制备 .     

Rate constants for the reactions of OH radicals with CH3OCF2CF3, CH3OCF2CF2CF3, and CH3OCF(CF3)2

The rate constants for the reactions of OH radicals with CH₃OCF₂CF₃, CH₃OCF₂CF₂CF₃, and CH₃OCF(CF₃)₂ have been measured over the temperature range 250–430 K. Kinetic measurements have been carried out using the flash photolysis, laser photolysis, and discharge flow methods combined respectively with the laser induced fluorescence technique. The influence of impurities in the samples was investigated by using gas‐chromatography. The following Arrhenius expressions were determined: k(CH₃OCF₂CF₃) = (1.90) × 10⁻¹² exp[−(1510 ± 120)/T], k(CH₃OCF₂CF₂CF₃) = (2.06) × 10⁻¹² exp[−(1540 ± 80)/T], and k(CH₃OCF(CF₃)₂) = (1.94) × 10⁻¹² exp[−(1450 ± 70)/T] cm³ molecule⁻¹ s⁻¹. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 846–853, 1999     

Upconversion and fluorescence spectral studies of Er3+/Yb3+-codoped Bi2Q3-GeO2-Ga2Q3-Na2O glasses

The absorption spectra and upconversion fluorescence spectra of Er3+/Yb3+-codoped natrium-gallium-germanium-bismuth glasses are measured and investigated. The intense green (533 and 549 nm) and red (672 nm) emission bands were simultaneously observed at room temperature. The quadratic dependence of the green and red emission on excitation power indicates that the two-photon absorption processes occur. The influence of Ga2C3 on upconversion intensity is investigated. The intensity of green emissions increases slowly with increasing Ga2O3 content, while the intensity of red emission increases significantly. The possible upconversion mechanisms for these glasses have also been discussed. The maximum phonon energy of the glasses determined based on the infrared (IR) spectral analysis is as low as 740 cm-1. The studies indicate that Bi2O3-GeO2-Ga2O3-Na2O glasses may be potential materials for developing upconversion optical devices.