基于科学核心观念建构的高中化学创新实验研究——以“多彩氧化亚铜纳米粒子的制备”为例

介绍了基于科学核心观念建构下制备多彩氧化亚铜纳米粒子的学生实验。利用葡萄糖还原班氏试剂的方法制备了氧化亚铜纳米粒子,并观察和讨论了不同条件下制备的粒子的颜色和粒径。整个实验安全、简单、现象明显、试剂用量少。本研究通过让学生参与科研的全过程,培养了学生的创新能力,促进了科学核心观念的建构。     

水基Fe3O4磁流体的制备

水基Fe3O4磁流体的制备;磁流体;化学共沉淀法;Fe3O4     

苯胺四聚体合成及电致变色器件制备——一个大学化学综合性实验

介绍一个研究探索型大学化学综合性实验——苯胺四聚体合成及其电致变色器件制备。内容包括苯胺四聚体的合成及简单的电致变色器件的制备和相关性能的测试。通过本实验的实践,可以让学生拓宽相关化学专业知识,提高学生综合实验操作技能和专业素质,让学生接触所学领域的前沿技术,激发学生对科学研究的兴趣,培养科研探究能力。     

席夫碱型有机小分子荧光探针的制备与表征——推荐一个综合化学实验

介绍一个综合型创新实验——有机小分子荧光探针的制备与表征。内容包括有机配体的合成及表征、荧光光谱的测试、金属离子的检测等。通过本实验的实践,既可以让学生更好地掌握无机、有机和分析化学相关专业知识,提升实验操作技能,又能让学生了解有机小分子荧光探针这一科研前沿领域,激发学生对科学研究的兴趣,培养科研能力。建议将本实验纳入本科高年级综合化学实验课。     

以四元相图为指导原理的硫酸钾制备实验在本科实验教学中的开展和探索

二步法制备硫酸钾是规模化生产钾肥的重要方法之一,本实验以四元相图的基本知识为理论指导开展硫酸钾制备实验。本实验通过无机复分解反应合成产物,采用传统滴定法、分光光度法与电感耦合等离子体原子发射光谱法(ICP-AES)相结合的测试方法对产物中离子进行分析检测,可实现基础操作与基本理论的同步提升,传统分析与现代仪器分析的有机结合。本实验原料易得、操作简便、现象明显、绿色环保,并且可以模块化教学,可拆分成多个实验环节,以适合不同学时的实验教学要求。该实验的开展既能让学生认识到化学理论知识在社会生产中所起的重要作用,又能培养学生的基本操作能力,提高学生的实践创新能力。     

基于STEAM教育的高中化学创新实验研究——以“化学红绿灯振荡反应最优条件探究”为例

介绍了STEAM教育下让学生使用靛蓝胭脂红为指示剂,探究了化学红绿灯振荡反应实验的最优条件。整个实验绿色、安全、操作简单、现象明显,试剂用量极少。旨在通过设置科学问题让学生体验整个科研过程,使学生能运用并掌握控制变量法解决实验问题,从而培养学生的创造力。     

磁性壳聚糖微球用于脲激酶的固定化研究I. 磁性壳聚糖微球的制备和表征

为制备用于固定化酶的磁性壳聚糖微球,本文首先用化学共沉淀法制备了磁流体,随后在磁流体存在下进行壳聚糖和戊二醛的共聚反应。结果表明,磁流体中的Ｆｅ３Ｏ４以水化物的状态存在,其含量为２．０４％,平均粒径为０．２～０．５ｕｍ左右;磁性壳聚糖微球的弱碱交换量随交联度的增加而减小,质量磁化率与微球粒径成反比。该微球具有良好的磁响应性,在外加磁场下可被快速的从溶液中分离出来。     

多酸配位聚合物的制备与表征——推荐一个综合化学实验

介绍了一个综合化学新实验--多酸配位聚合物的制备与表征。通过杂多酸和有机配体的合成、多酸配位聚合物的制备和性能表征,使学生了解多酸配位聚合物这一无机合成化学前沿领域,在引导学生进行材料合成及性质表征的过程中,提高学生对已学知识融会贯通的能力,提升学生学习化学的兴趣。本实验综合了无机、有机化学知识点以及实验、仪器操作和数据分析能力的培养,可纳入高年级综合化学实验。     

无皂乳液聚合法制备Fe3O4@P(St-GMA)复合微球

用化学共沉淀法制备了磁性四氧化三铁纳米粒子. 在油酸和氨水的作用下, 使之分散在水中, 得到了水分散的磁流体. 在水基磁流体的存在下, 进行苯乙烯和甲基丙烯酸缩水甘油酯(GMA)的无皂乳液共聚合, 得到了Fe₃O₄@P(St-GMA)复合微球. 综合考察了反应温度、磁流体和单体的用量、引发剂的用量对聚合转化率的影响, 并用TEM, TGA和VSM对磁性复合微球进行了表征.     

铜卟啉合成及其敏化二氧化钛光催化剂的制备——一个大学化学综合性实验

介绍了一个大学化学综合性实验——铜卟啉合成及其敏化二氧化钛光催化剂的制备。该实验是一个科研转化的大学生综合化学实验,内容包括铜四苯基卟啉的合成、铜四苯基卟啉敏化二氧化钛光催化剂的制备,以及光催化剂对水中有机污染物的降解。通过本实验,可以拓宽学生的化学专业知识,提高学生的综合实验操作技能,激发学生对科学研究的兴趣,培养学生的科研探究能力。     

Phase relations in the K2W2O7-K2WO4-KPO3-Bi2O3 system and structure of K6.5Bi2.5W4P6O34

The phase relations in the cross-section of the K₂W₂O₇-K₂WO₄-KPO₃ containing 15 mol% Bi₂O₃ were undertaken using flux method. Crystallization fields of K_6.5Bi_2.5W₄P₆O₃₄, K₂Bi(PO₄)(WO₄), Bi₂WO₆, KBi(WO₄)₂ and their cocrystallization areas were identified. Novel phase K_6.5Bi_2.5W₄P₆O₃₄ was characterized by single-crystal X-ray diffraction: sp. gr. P−1, a=9.4170(5), b=9.7166(4), c=17.6050(7) Å, α=90.052(5)°, β=103.880(5)° and γ=90.125(5)°. It has a layered structure, which contains {K₇Bi₅W₈P₁₂O₆₈}_∞ layers stacked parallel to ab plane and sheets composed by potassium atoms separating these layers. Sandwich-like {K₇Bi₅W₈P₁₂O₆₈}_∞ layers are assembled from [W₂P₂O₁₃]_∞ and [BiPO₄]_∞ building units, and are penetrated by tunnels with K/Bi atoms inside. FTIR-spectra of K₂Bi(PO₄)(WO₄) and K_6.5Bi_2.5W₄P₆O₃₄ were discussed on the basis of factor group theory.     

KCl-KBO2-K2CO3, K2MoO4-KBO2-K2CO3, and K2WO4-KBO2-K2CO3 ternary systems

phase diagrams of KCl-KBO₂-K₂CO₃, K₂MoO₄-KBO₂-K₂CO₃, and K₂WO₄-KBO₂-K₂CO₃ ternary systems were studied by a calculation-experimental method and differential thermal analysis (DTA). The coordinates of ternary eutectics were determined to be E ₁: 622°C, 8.5 mol % KBO₂, 56.5 mol % KCl, and 35 mol % K₂CO₃; E ₂: 710°C, 23 mol % KBO₂, 43 mol % K₂CO₃, and 34 mol % K₂MoO₄; E ₃: 710°C, 23 mol % KBO₂, 43 mol % K₂CO₃, and 34 mol % K₂WO₄. The specific heats of melting of the eutectics were determined.     

Sol-gel synthesis of K3InF6 and structural characterization of K2InC10O10H6F9, K3InC12O14H4F18 and K3InC12O12F18

K₃InF₆ is synthesized by a sol-gel route starting from indium and potassium acetates dissolved in isopropanol in the stoichiometry 1:3, with trifluoroacetic acid as fluorinating agent. The crystal structures of the organic precursors were solved by X-ray diffraction methods on single crystals. Three organic compounds were isolated and identified: K₂InC₁₀O₁₀H₆F₉, K₃InC₁₂O₁₄H₄F₁₈ and K₃InC₁₂O₁₂F₁₈. The first one, deficient in potassium in comparison with the initial stoichiometry, is unstable. In its crystal structure, acetate as well as trifluoroacetate anions are coordinated to the indium atom. The two other precursors are obtained, respectively, by quick and slow evaporation of the solution. They correspond to the final organic compounds, which give K₃InF₆ by decomposition at high temperature. The crystal structure of K₃InC₁₂O₁₄H₄F₁₈ is characterized by complex anions [In(CF₃COO)₄(OH_x)₂]^(5−2x)− and isolated [CF₃COOH_2−x]^(x−1)− molecules with x=2 or 1, surrounded by K⁺ cations. The crystal structure of K₃InC₁₂O₁₂F₁₈ is only constituted by complex anions [In(CF₃COO)₆]³⁻ and K⁺ cations. For all these compounds, potassium cations ensure only the electroneutrality of the structure. IR spectra of K₂InC₁₀O₁₀H₆F₉ and K₃InC₁₂O₁₂F₁₈ were also performed at room temperature on pulverized crystals.     

Solubility in the Na2Cr2O7-(NH4)2Cr2O7-K2Cr2O7-H2O system

Solubility in the Na₂Cr₂O₇-(NH₄)₂Cr₂O₇-K₂Cr₂O₇-H₂O four-component water-salt system at 25, 50, and 75°C was studied for the first time. Phase field boundaries for individual salts and potassium and ammonium dichromate solid solutions, monovariant lines, and invariant points were determined. Experimental data were used to optimize the looped isohydric process of potassium dichromate preparation involving additional salts.     

Li2SO4-Na2SO4-H2O和Li2SO4- K2SO4-H2O溶液的体积性质

本文用高精度数字式振荡管密度计测定了288K至318K温度范围内Li₂SO₄ + Na₂SO₄ + H₂O和 Li₂SO₄ + K₂SO₄ + H₂O三元体系的密度。混合溶液的离子强度范围从0.1到4.5 mol.kg_–1,混合溶液中Na₂SO₄和K₂SO₄的离子强度分数为0.2,0.4,0.6和0.8。用密度实验值拟合得到了不同温度下Pitzer离子相互作用模型混合参数θ_V和 ψ_V,模型的计算值与实验值的偏差在±0.002 g.cm_–3以内。用Pitzer模型计算了不同离子强度下三元体系的混合体积。     

NaBO2-NaCl-Na2CO3, NaBO2- Na2CO3-NaMoO4, NaBO2- Na2CO3-NaWO4, and NaBO2-NaCl-Na2WO4 ternary systems

The phase diagrams of the NaBO₂-NaCl-Na₂CO₃, NaBO₂-Na₂CO₃-Na₂MoO₄, NaBO₂- Na₂CO₃-Na₂WO₄, and NaBO₂-NaCl-Na₂WO₄ ternary systems were studied by a calculation-experimental method and differential thermal analysis. The coordinates of ternary eutectics were determined: E ₁: 612°C, 16 mol % NaBO₂, 42 mol % NaCl, and 42 mol % Na₂CO₃; E ₂: 568°C, 12 mol % NaBO₂, 28 mol % Na₂CO₃, and 60 mol % Na₂MoO₄; E ₃: 575°C, 12 mol % NaBO₂, 32 mol % Na₂CO₃, and 56 mol % Na₂WO₄; E ₄: 628°C, 8 mol % NaBO₂, 20 mol % NaCl, and 72 mol % Na₂WO₄; and E ₅: 655°C, 9 mol % NaBO₂, 53 mol % NaCl, and 38 mol % Na₂WO₄.     

Extension of the La7Mo7O30 structural type with La7Nb3W4O30 and La7Ta3W4O30 compounds

Two compounds of formula La₇A₃W₄O₃₀ (with A=Nb and Ta) were prepared by solid-state reaction at 1450 and 1490 °C. They crystallize in the rhombohedric space group R-3 (No. 148), with the hexagonal parameters: , and , . The structure of the materials was analyzed from X-ray, neutron and electronic diffraction. These oxides are isostructural of the reduced molybdenum compound La₇Mo₇O₃₀, which are formed of perovskite rod along [111]. An order between (Nb, Ta) and W is observed.     

Preparation and structure of NaSr0.5Al2B2O7 and NaCa0.5Al2B2O7

Two compounds NaSr_0.5Al₂B₂O₇ and NaCa_0.5Al₂B₂O₇, have been found to crystallize into a new structure type by Rietveld refinement from X-ray powder diffraction data. Their structure belongs to hexagonal space group P6₃/m, with lattice parameters of , for NaSr_0.5Al₂B₂O₇ and , for NaCa_0.5Al₂B₂O₇, respectively. The structure is built up by [Al₂B₂O₇]²⁻ double layer and Na⁺/Ca²⁺ or Na⁺/Sr²⁺ ions alternatively stacking along the c-axis. The sites in the inter-double layer are fully occupied jointly by Na and Ca or Sr, but the intra-double layer sites are only half occupied solely by Na. A mechanism of the transition of the structure from CaAl₂B₂O₇ to present structure type by replacing only 1% Ca by Na (2%) as observed by Chang and Keszler (Mater. Res. Bull. 33 (1998) 299) is also proposed.     

SnSbBiS4-SnS and SnSbBiS4-Sn2Sb6S11 sections of the SnS-Sb2S3-Bi2S3 ternary system

SnSbBiS₄-SnS and SnSbBiS₄-Sn₂Sb₆S₁₁ sections were studied by physicochemical methods (DTA, X-ray powder diffraction, microstructure observation, and microhardness measurements). These sections were found to be eutectic quasi-binary sections of the SnS-Sb₂S₃-Bi₂S₃ ternary system. Solid solution regions based on the initial components were found on either side of the sections. Alloys in the solid solution region are p-type semiconductors.     

Theoretical study of polyoxide clusters B20O30, Al20O30, V20O50, Si20O30H20, and Si20O30F20

The structural, electronic, and vibrational characteristics and energies of the isolated polyoxide clusters B₂₀O₃₀, Al₂₀O₃₀, V₂₀O₅₀, Si₂₀O₃₀H₂₀, and Si₂₀O₃₀F₂₀ and their complexes with the H⁻ ion and ammonia complexes Al₂₀O₃₀ · nNH₃ have been calculated by the density functional theory B3LYP method with different basis sets. The computation results show that the symmetric closo structure I _h with oxygen bridges located above the centers of the faces of an empty [M₂₀] dodecahedron is more favorable for V₂₀O₅₀, Si₂₀O₃₀H₂₀, and Si₂₀O₃₀F₂₀. For B₂₀O₃₀, the cage closo isomer is also more favorable than the other isomers, but its structure is severely distorted as compared to a dodecahedron and has a symmetry close to C ₃ . For Al₂₀O₃₀, the I _h structure corresponds to a high-lying local minimum of the potential energy surface. For Al₂₀O₃₀, a set of unusual puckshaped isomers of symmetry C _i , with different numbers of four-coordinate atoms ^IVAl and three-coordinate atoms ^IIIO, was localized; these structures are more than 90 kcal/mol more favorable than the dodecahedron I _h . The most favorable isomer of Al₂₀O₃₀ contains twelve four-coordinate atoms ^IVAl and four five-coordinate atoms ^VAl. The energies of dissociation of the most favorable M₂₀O₃₀ clusters into the M₂O₃ (C _2v ) and M₄O₆ (T _d ) fragments and, in the case of Al₂₀O₃₀, also into the Al₈O₁₂ (O _h ) and Al₁₂O₁₈ (D _3d ) fragments, have been estimated. The conclusion has been drawn that these clusters can, in principle, exist and can be experimentally detected in the isolated state. Analogous calculations have been performed for ammonia complexes Al₂₀O₃₀ · nNH₃ with n varying from 1 to 20. The effect of solvation on the relative stability of the dodecahedral and puckshaped isomers of the Al₂₀O₃₀ cluster is observed. The isomers with ammonia molecules in their first coordination sphere become much closer to one another on the energy scale; however, the dodecahedron remains a considerably less favorable intermediate. Original Russian Text ? O.P. Charkin, N.M. Klimenko, D.O. Charkin, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 4, pp. 624–635.