[Cr(NH3)6]3+离子在氨水中能直接形成吗?

通过实验事实和理论推算,说明在含有Cr~(3+)离子的溶液中加入NH_3·H_2O,主要生成的是Cr(OH)_3,而不是[Cr(NH_3)_6]~(3+)离子.     

为什么[Co(NH3)5Cl]2+与[Co(NH3)6]3+的颜色不同?

结合对［Ｃｏ（ＮＨ３）５Ｃｌ］＾２）与［Ｃｏ（ＮＨ３）６］＾３＋的颜色的比较，阐述配体场理论中有关电子组态、能级、轨道、配体场谱项及谱项间跃迁等基本概念及难点。即使不做严格的量子化学计算，从直观的物理模型、简单的分子轨道理论、群论方法及有关谱图中也能获得有用信息。     

对“关于氯化钠晶格能的计算”一文的勘误

对“关于氯化钠晶格能的计算”一文的勘误《大学化学》１９９１年第４期１５页刊登了“关于氯化纳晶格能的计算”一文，读者鲁敬荣来稿指出该文中关于晶格能Ｌ０和Ｌ２９８的换算关系推导及结果有误，编辑部诚恳接受意见。现改正如下：Ｎａ＋（ｇ）＋Ｃｌ－（ｇ）─→Ｎａ...     

关于“铝离子——迷失的环节”(征答8)的讨论

本刊在1987年第2卷第4期第52页上曾刊出征答(8),至今已收到一些读者的应答稿件,在此选出何应森、郭志斌两位同志的文稿,经补充摘要刊出,并请本栏目的主持人、北京医科大学药学院王夔教授作一小结.     

[Co(NH3)6]2+催化乙炔氧化缩聚合成β型线型碳

在T=35℃的条件下,以盐酸为酸化剂、[Co(NH3)6]2+为催化剂,催化乙炔氧化缩聚合成了β型线型碳.通过红外光谱、拉曼光谱和x-衍射对产物进行了结构表征.pH=6,六水氯化钴(Ⅱ)用量为0.4g时,β型线型碳的产率为61.18%,其中Co(Ⅱ)的含量为1.72%.TG和DTA分析结果表明:在227.4℃时,β型线...     

对“三草酸合铁(Ⅲ)酸钾的制备”的改进

在Ｋ３［Ｆｅ（Ｃ２Ｏ４）３］·３Ｈ２Ｏ合成过程中,当草酸加入Ｈ２Ｏ２氧化ＦｅＣ２Ｏ４·２Ｈ２Ｏ产物制备Ｋ３［Ｆｅ（Ｃ２Ｏ４）３］·３Ｈ２Ｏ溶液时,原实验条件控制不严格,易发生草酸还原高铁的副反应而导致产品不纯。本文通过改进草酸加入方式和酸溶终了ｐＨ的控制,可降低副反应,提高产品质量。     

First example of the cluster ammine complex [Re6Se7Br(NH3)6]3+: synthesis and structure of the [Re6Se7Br(NH3)6][Re6Se7BrBr6]·12H2O salt

The reaction of Cs₃[Re₆Se₇BrBr₆] with aqueous ammonia afforded the octahedral rhenium ammine cluster complex cation [Re₆Se₇Br(NH₃)₆]³⁺. This cation crystallized as the [Re₆Se₇Br(NH₃)₆][Re₆Se₇BrBr₆]·12H₂O compound. The crystal structure of this compound was established. The presence of the NH₃ ligands in the coordination environment about the Re atom was confirmed by thermogravimetry, vibrational spectroscopy, and high-resolution mass spectrometry. The resulting compound is the first example of salts composed of the cluster cation and cluster anion possessing the same {Re₆Se₇Br} cluster core.     

[Co(NH3)6]2[Cd8(C2O4)11(H2O)4]·8H2O：A 5-connected sqp topological metal-organic framework co-templated by Co(NH3)63+ cation and (H2O)4 cluster

In our efforts to construct new metal-organic frameworks (MOFs) by template-directing method, a new cadmium oxalate, [Co(NH3)6]2[Cd8(C2O4)11(H2O)4]·8H2O (denoted HNU-1), has been synthesized under hydrothermal condition in the presence of Co(NH3)6Cl3. The crystal structure of HNU-1 was determined by single-crystal X-ray diffraction (monoclinic, C2/c), a = 11.126(2)Å, b = 17.361(4)Å, c = 16.119(3)Å, β = 102.40(3)°, V = 3040.8(10)Å3 and Z = 8. The open framework of HNU-1 contains 12-ring channels and exhibits a 5-connected sqp topological network with dinuclear Cd(Ⅱ) clusters acting as nodes. The Co(NH3)63+ cations and unusual hydrogen-bonded (H2O)4 clusters are found in the 12-ring channels with an alternative arrangement. It is believed that the (H2O)4 clusters play a co-templating role in the crystallization of HNU-1.     

The phenomenon of conglomerate crystallization: XXXVII: The crystallization behavior of the Cr(III) and Co(III) amine carbonates [Cr(en)2CO3]I (I) and NH4{[cis-β-Co(trien)Co3]2}(PF6)3 (II)

[Cr(en)₂CO₃]I (I), ICoO₃N₄C₅H₁₆, crystallizes from water at 21°C in space groupP2₁/c (no. 14), with lattice constantsa=7.298(4),b=8.622(8),c=17.577(6)Å,=91.29(4)°;V=1105.59 ų andd(calc; MW=359.11, Z=4)=2.157 g cm^–3. A total of 2825 data points were collected over the range of 4°250°; of these, 1855 (independent and withI3(I)) were used in the structural analysis. Data were corrected for absorption (=37.657 cm^–1) and the transmission coefficients ranged from 0.4850 to 0.9991. The finalR(F) andR _w(F) residuals were, respectively 0.134 and 0.113. The cations exist in the lattice as the enantiomeric pair () and (). NH₄{[cis--Co(trien)CO₃]₂}(PF₆)₃ (II), Co₂P₃F₁₈O₆N₉C₁₄H₄₀, crystallizes from water at 21 °C in space groupP2₁/c (no. 14), with lattice constantsa=10.397(2),b=20.292(3),c= 27.082(4) Å,=100.30(3)°;V=3545.70 ų andd(calc; MW=983.29, Z=4)=1.842 g cm^–3. A total of 3724 data were collected over the range of 4°250°; of these, 2653 (independent and withI3(I)) were used in the structural analysis. Data were corrected for absorption (=12.031 cm^–1) and the transmission coefficients ranged from 0.8326 to 0.99985. The finalR(F) andR _w (F) residuals were, respectively 0.104 and 0.124. The cations exist in the asymmetric unit as() and()[cis--Co(trien)CO₃]⁺ pairs. The three independent PF₆ ^– anions exhibit the usual high thermal motion typical of these species and the NH₄ ⁺ cation is either disordered or exhibits high thermal motion also (its H atoms could not be found in difference maps).     

Crystal structure and mössbauer spectroscopy studies of the ferrimagnetic complex bimetallic salt hexaamminechromium (III) hexachloroferrate (III), [Cr(NH3)6][FeCl6]

The crystal and molecular structures of the ferrimagnetic bimetallic complex salt hexaamminechromium(III) hexachloroferrate(III), [Cr(NH₃)₆][FeCl₆], have been determined from single-crystal, three-dimensional x-ray diffraction counter data. The compound crystallizes as orange coloured crystals in the space groupC2/c of the monoclinic system with Z=4 and has cell dimensionsa=11.325(1) ?,b=11.387(1) ?,c=11.233(1) ?, and β=90.83(1)?. The structure was refined by using segmented block diagonal least-squares techniques to discrepancy indices R and R_w of 0.0233 and 0.0285, respectively. The metal ions occupy sites with symmetry and are nearly octahedrally coordinated. In the [FeCl₆]³⁻ anion there are three independent Fe−Cl distances with a mean of 2.393(2) ?, and the maximum angular deviation from octahedral geometry is 1.2⁰. In the [Cr(NH₃)₆]³⁺ cation, the mean of the three independent Cr−N distances is 2.079 (7) ?, and the maximum angular deviation from octahedral geometry is 0.7⁰. The structural data provide an explanation for the observed quadrupole splitting of 0.214 mms⁻¹ as seen in the M?ssbauer spectrum at 292.6 K and reveal superexchange pathwaysvia close amine proton-chloride anion contacts with lead to 3D-ferrimagnetic ordering near 2.8 K.     

[Co（NH3）6]Cl3实验中制备条件对配合物形成影响的讨论

针对[Co(NH3)6]Cl3制备实验中,反应条件不同会导致生成具有不同组成的Co(Ⅲ)氨配合物这一问题,系统探讨了制备过程中在配体NH3、Cl-和H2O共存时,[Co(NH3)6]Cl3、[Co(NH3)5Cl]Cl2和[Co(NH3)5(H2O)]Cl3这三种Co(Ⅲ)氨配合物的生成条件和稳定性。通过对比分析各自的形成过程和制备条件,将化学原理应用于解释实验现象,可培养学生结合理论知识对实验案例进行对比分析的探究能力。     

对“快速(高压)液体色谱”一文的商榷

《分析化学》74年第2期刊登了“快速(高压)液体色谱”一文,向广大读者扼要全面地介绍了高压液体色谱的进展情况,对这项技术在我国广泛开展起了一定的作用。但文中个别概念尚欠确切,有些资料也与目前高压液体色谱的发展水平不相符,在此提出与作者和广大读者共商讨: (一)关于凝胶渗透色谱的分离规则:凝胶色谱是液体色谱的一种,它具有与其他液体色谱不同的分离规则。作者认为“凝胶渗透基本上是按照溶质的分子量大小来分离的。”这样提法是值得商榷的。严格说,凝胶色谱是按分子尺寸的大小,而不是分子量来分离的。分子尺寸与分子量显然是不同的两个概念。分子尺寸与分子在溶液中的     

纳米(NH4)3PMo6W6O40的室温固相合成及形成机理

以H3PMo6W6O40•23H2O和(NH4)2C2O4•H2O为原料，采用室温固相反应合成出(NH4)3PMo6W6O40•6H2O产物，用元素分析、IR、UV-Vis、XRD、TEM、TG-DTA、BET等手段确定其组成、结构和性能.结果表明，产物为纳米粒子，平均粒径为10 nm.纳米粒子保持着杂多阴离子的Keggin特征结构，比表面积为167.6 m2•g－1，且在465 ℃以下具有良好的热稳定性.反应中反应热能、结晶水和生成物H2C2O4•2H2O对形成小粒径的(NH4)3PMo6W6O40纳米粒子起关键作用.     

试论“磨合期”教学——-对《无机化学(二)实验》课程教学的体会

试论“磨合期”教学———对《无机化学（二）实验》课程教学的体会金松林谢高阳（复旦大学化学系上海２００４３３）我校三年级下学期设置的《无机化学（二）实验》课程从１９８８年初开设至今已九年了。它的出现改变了大学理科化学专业在一年级做低层次无机实验，到四年...     

Properties and Extraction for [Ni(NH3)6]2+ of ATPS-a Formed by Aqueous Cationic–Anionic Surfactant Mixtures

The properties and extraction for [Ni(NH₃)₆]²⁺ of anionic aqueous two-phase systems (ATPS-a) that formed in mixtures of cetyltrimethylammonium bromide (CTAB) and excess sodium dodecyl sulfate (SDS) aqueous solutions were investigated. The results showed that the properties and extraction effects were strongly affected by the surfactant concentration, the temperature of system, and the mole fraction of surfactants. The increase of temperature induces narrower phase region and larger phase volume ratio. In addition, [Ni(NH₃)₆]²⁺ was extracted into the surfactant-rich phase with higher distribution coefficient when the liquid crystal had the birefringent properties. Moreover, the distribution coefficient can be improved through reducing the concentration of surfactant from 0.15 to 0.05 mol · L^?1 or increasing mole fraction of CTAB from 21.9% to 23.1%. The results showed that ATPS of cationic–anionic surfactants was efficient for [Ni(NH₃)₆]²⁺ extraction with distribution coefficients of 13.5 when the total surfactant concentration was 0.05 mol · L^?1, mole fraction of CTAB was 21%, and temperature was 34°C.     

二维配位聚合物(NH3+CH2CH2NH3+)(NH2CH2CH2NH3+)2[(VO)4(PO4)4(H2O)2]·2H2O的水热合成及晶体结构

无机-有机杂化钒氧酸盐由于其结构的多样性以及在催化、医药、光、电、磁等材料领域中的应用前景而受到人们的广泛关注。近年来这一研究领域的重大进步是将有机氮配体或者过渡金属配合物直接连接到矾氧骨架上以获得各种新奇结构。合成出许多属于L/V/O、MXLY/V/O、L/P/V/O和MXLY     

Relativistic Jahn—Teller effect G<Subscript>g</Subscript>[3/2]×(t<Subscript>2g</Subscript> + e<Subscript>g</Subscript>) in cubic and octahedral molecules

The properties of the symmetry of the vibronic Hamiltonian of the multimode relativistic Jahn—Teller effect G_g[3/2]×(t_2g + e_g) in cubic and octahedral molecules are studied. The Hamiltonian considered corresponds to the half-integer spin of the electron shell and the linear approximation on the vibrational normal modes t_2g and e_g. The angular variables were separated, and biradial dynamic equations and analytical expressions for the biradial potential energy surfaces were obtained. The positions of the low-lying resonances in two upper potential “bowls” were found.     

对Ag(NH3)2＋中的Ag＋是sp 杂化成键的商榷

对Ａｇ（ＮＨ_３）_２~＋中的Ａｇ~＋是ｓｐ杂化成键的商榷夏泽吉（四川达县师专化学系６３５０００）目前在国内一些高等院校使用的《无机化学》［１，２］教材中，对Ａｇ（ＮＨ３）配离子中的Ａｇ（Ⅰ）均认为是ｓｐ杂化成键，而且有的《无机化学》［３］为了强调形成配...     

Carbonate complexes [C(NH2)3]6[An(CO3)5] · nH2O (An = Th, U, Np, and Pu; n = 3 and 4): Synthesis and structures

Two series of isostructural double An(IV) and guanidinium carbonates were obtained as single crystals of the formula [C(NH₂)₃]₆[An(CO₃)₅] · nH₂O (An = Th, U, Np, and Pu; n = 3 (I) and 4 (II)) and examined by X-ray diffraction. For the Pu(IV) complexes, a = 10.490(2) Å, b = 33.798(5) Å, c = 10.519(2) Å, β = 119.414(7)°, space group P2₁/c, Z = 4, R = 0.0369 (I) and a = 16.0895(18) Å, b = 13.1458(14) Å, c = 16.6951(18) Å, β = 108.116(6)°, space group C2/c, Z = 4, R = 0.0171 (II). Both series of complexes contain the anions [An(CO₃)₅]^6?, in which the An atom is coordinated to five chelating bidenate carbonate ions. The coordination polyhedra of the An atoms are distorted bicapped square antiprisms. Within both the series, the An-O bond lengths decrease monotonically only for the sequence Th-U-Np. The average Np-O and Pu-O bond lengths in both tri- and tetrahydrates are virtually equal. The IR and electronic absorption spectra of the complexes obtained were studied. The absorption bands due to the f-f transitions experience bathochromic shifts in the spectra of the U⁴⁺ and Pu⁴⁺ carbonate complexes and hypsochromic shifts in the spectra of the Np⁴⁺ complexes.     

三价铬离子的水解聚合作用的研究(Ⅲ)——在较高浓度下Cr3+的水解聚合状态

本文用pH法研究了Cr³⁺在较高浓度下的水解聚合状态,发现了同一种Cr³⁺水解体系的第二种“根+节”配位化合物--Cr[Cr(OH)]_n^(3+2n)+(n=1,2)。其水解平衡常数为lgβ_1,2=-2.68,lgβ_2,3=-3.84。