CoC2O4·2H2O纳米晶形貌可控合成

通过简单调节反应介质热塑性酚醛树脂与乙二醇配比,选择性地制备了CoC2O4·2H2O纳米棒和纳米片晶体或其两种形貌晶体混合物.样品热重和差示扫描量热(TG-DSC)、X射线粉体衍射(XRD)、场发射扫描电镜( FESEM)实验表明:以热塑性酚醛树脂为反应介质得到了COC2O4·2H2O纳米棒;以乙二醇为反应介质得到了CoC2O4·2H2O纳米片;逐渐增大乙二醇和酚醛树脂质量比,实现了CoC2O4·2H2O形貌由纳米棒形貌转变为纳米片形貌.基于不同晶体形貌和实验结果,提出了棒状和片状COC2O4·2H2O可能的形成机理模型以解释两种形貌COC2O4·2H2O纳米晶的生长行为.     

区熔法制备Al2O3/MgAl2O4共晶陶瓷

利用感应区熔法制备了Al2O3/MgAl2O4共晶陶瓷.当坩埚壁温为2150℃、行走速度为5 mm/h时,获得了φ10 mm×104 mm表面光滑的圆棒.结果表明共晶陶瓷由Al2O3相和MgAl2O4相组成,分别按照(110)(311)晶面生长;Al2O3相为基体相,MgAl2O4相以非连续的片状均匀地分布在基体相之中.定向凝固共晶陶瓷的密度是理论值的99;;硬度和断裂韧性分别达到18.7 GPa和3.74 MPa·m1/2,约是预烧结体的2倍.气孔和界面非晶相的消失以及以单晶形态存在的Al2O3基体相,有效提高了材料的硬度和断裂韧性.     

β-BaB2O4纳米粉体的制备

报道了采用溶胶一凝胶法合成β-BaB2O4纳米粉的方法.该法的特点是反应体系中添加一种表面改性剂HYPO,改变了颗粒的表面状态,防止了氧桥键的形成,从而避免了颗粒的硬团聚.产物经500℃烧结后,β-BaB2O4粉体的平均粒径为70nm,颗粒分布均匀.本文同时对该工艺中引起粉体硬团聚的各个因素作了初步的探讨.     

Crystal structures of acid ethylenediaminetetraacetates [Cd(H2 Edta)(H2O)] · 2H2O and [Mn(H2O)4][Mn(HEdta)(H2O)]2 · 4H2O

The crystal structures of [Cd(H₂ Edta)(H₂O)] · 2H₂O (I) and [Mn(H₂O)₄][Mn(HEdta)(H₂O)]₂ · 4H₂O (II) are studied by X-ray diffraction [R ₁ = 0.0209 (0.0272), wR ₂ = 0.0571 (0.0730) for 2551 (4025) reflections with I > 2σ(I) in I (II), respectively]. Structure I contains mononuclear [Cd(H₂ Edta)(H₂O)] complexes with the C ₂ symmetry, and structure II contains centrosymmetric trinuclear [Mn(H₂O)₄][Mn(HEdta)(H₂O)]₂ complexes. In I and II, the protonated ligands are hexadentate (2N + 4O), and the water molecule increases the coordination number of the metal atom to seven. The acid protons participate in short intermolecular hydrogen bonds, which are symmetric in II and asymmetric in I.     

Studies of ternary Li2SO4–Li2O–P2O5 glasses

Glasses in a wide range of compositions in the ternary system xLi₂SO₄–yLi₂O–zP₂O₅ where x ranges from 0 to 30 mol%, y ranges from 35 to 55 mol% and z ranges from 25 to 50 mol% have been prepared and their properties measured using infra-red, Raman, and ³¹P magic angle spinning nuclear magnetic resonance spectroscopic techniques. We conclude that a random close packing of phosphate and sulphate ions which also leads to formation of connected voids in the structure is consistent with our data. There is also evidence for formation of condensed sulphate–phosphate species in the liquid which may be retained in the glass structure.     

Fe2O3-CO3O4共掺杂MgO-Al2O3-SiO2体系的红外辐射性能研究

采用固相反应法制备Fe2O3-Co3O4共掺杂MgO-Al2O3-SiO2体系的复合陶瓷材料,并通过XRD、SEM、XPS以及红外辐射测试等方法研究了样品的结晶行为与红外辐射性能.结果表明:Fe2 O3和Co3 O4共掺杂MgO-Al2 O3-SiO2体系后离子分布改变并生成混合尖晶石,从而引起品格畸变,从而有效提高材料的红外辐射性能.材料的红外发射率与其晶格畸变程度具有相同的变化趋势,并随Fe2 O3与Co3O4质量之比(R)的增加呈非线性变化.当R=3∶2时,材料在8 ～ 14 μm波段的辐射率可达0.92.     

[Co(H2O)6](C18H15O4SO3)2·4H2O的合成和晶体结构

以芒柄花素为先导化合物,合成了水溶性的[Co(H2O)6](C18H15O4SO3)2·4H2O,并采用IR, 1H NMR, TG-DTA, XRD和单晶X射线衍射法对其结构进行了表征.单晶X射线衍射结果表明:[Co(H2O)6]2+、C18H15O4SO 3和H2O之间存在多种氢键,形成晶体结构中的亲水区.异黄酮骨架间反平行排列,面对面和边对面芳香堆积作用同时存在于其中,构成晶体结构中的疏水区.磺酸根是连接亲水区和疏水区的桥梁.氢键、芳香堆积作用以及阴阳离子之间的静电引力共同将标题化合物组装成具有三维网络结构的超分子.     

透明导电氧化物MgIn2O4的研究进展

透明导电氧化物(TCO)材料由于它的特殊性质,在平板显示器和太阳能电池等方面得到了广泛的应用.MgIn2O4作为一种新型的尖晶石结构的透明导电材料,也受到了研究人员的重视,成为近年来的研究热点,常用的MgIn2O4材料制备方法包括固相合成、磁控溅射、脉冲激光沉积等,本文综合国外学者的一些研究成果,介绍了目前MgIn2O4材料的制备方法及其性能提高和应用.     

New Crystals in the CsHSO4–CsH2PO4–NH4H2PO4–H2O System

Crystallography Reports - The phase equilibria in the CsHSO4–CsH2PO4–NH4H2PO4–H2O four-component aqueous salt system have been studied. The crystallization ranges and solubilities...     

感应区熔法制备Al2O3/MgAl2O4/ZrO2共晶陶瓷

利用感应区熔法制备了Al2O3/MgAl2O4/ZrO2共晶陶瓷.当坩埚壁温为2200℃、行走速度为2mm/h时,制备了φ10 mm ×62 mm表面光滑致密的陶瓷样品.扫描电镜微观组织图显示Al2O3相和MgAl2O4相为基体相,ZrO2相以棒状镶嵌在基体中.定向凝固共晶陶瓷硬度和断裂韧性达到12 GPa和6.1 MPa·m1/2,为预烧结体的2倍和1.7倍.气孔和晶界的消失及细小规整ZrO2相在基体中的弥散分布,有效提高了材料的硬度和断裂韧性.     

Synthesis and structure of (NH4)3[UO2(C3H2O4)2(NCS)] · 2H2O

Malonate-thiocyanate complex (NH₄)₃[UO₂(C₃H₂O₄)₂(NCS)] · 2H₂O is synthesized and studied by X-ray diffraction. The compound crystallizes in the monoclinic system: a = 13.9983(4) Å, b = 8.1947(2) Å, c = 16.4678(4) Å, β = 100.846(1)°, space group Cc, Z = 4, and R = 0.0158. The main structural units of the crystal are mononuclear [UO₂(C₃H₂O₄)₂(NCS)]^3? groups belonging to the AB ₂ ⁰¹ M ₁ crystal chemical group of uranyl complexes (A = UO ₂ ²⁺ , B ⁰¹ = C₃H₂O ₄ ^2? , M ¹ = NCS^?). Discrete uranium-containing groups are connected by electrostatic interactions with ammonium ions and by hydrogen bonds. Some specific structural features of crystals containing [UO₂(L)₂(NCS)]^3? complexes, where L is the oxalate or malonate ion, are discussed.     

三维网络结构NiCo2S4@NiCo2O4复合电极的制备及其性能

超级电容器具有更大的功率密度、优秀的循环稳定性、极快的充放电速度、超长的循环寿命以及环境友好等突出特点,其性能与构件关系密切,其中最根本的就是组成它的电极材料。本研究主要采用传统的水热法制备出钴酸镍(NiCo₂O₄)电极材料,进而通过离子交换(二次水热)制得镍钴硫(NiCo₂S₄),最后利用化学浴沉积(CBD)法使其与钴酸镍复合,得到最终所需的三维网络结构NiCo₂S₄@NiCo₂O₄复合电极。经过表面形貌表征、循环伏安测试、恒电流充放电测试以及比电容计算分析等可以证明:三维网络结构NiCo₂S₄@NiCo₂O₄复合电极的比电容及循环稳定性等远远优于复合前单一的纯NiCo₂O₄电极材料,具有极大应用前景。     

Synthesis and crystal structure of [Co(phen)(H2O)4](SO4)⋅2(H2O)

The title complex, [Co(phen)(H₂O)₄](SO₄)2(H₂O) (phen = 1,10-phenanthroline) was prepared in aqua tert-butylperoxohydrogen solution. X-ray single crystal structure determination reveals that the complex consists of a phenanthrolinatocobalt(II)tetrahydrate dication, two uncoordinated water molecules and a sulfate anion. It crystallizes in the orthorhombic space group Pbca with a = 8.856(1), b = 18.318(3), c =21.918(5) Å, V = 3555.6(11) ų. The coordination geometry at each cobalt(II) atom is a slightly distorted octahedron.     

Metal-hydroxycarboxylate interactions: syntheses and structures of K2[VO2(C6H6O7)]2·4H2O and (NH4)2[VO2(C6H6O7)]2·2H2O

Potassium and ammonium dimeric (citrato)dioxovanadium(V) hydrate K₂[VO₂(H₂cit)]₂·4H₂O1 and (NH₄)₂[VO₂(H₂cit)]₂·2H₂O2 (H₄cit=citric acid) have been prepared and characterized by X-ray structure analyses. Vanadate1 crystallizes in the monoclinic space groupP2₁/n (No. 14) with unit cell parameters:a=9.304(2),b=11.756(2),c=11.911(2)Å, =111.72(3)°, andD _c=1.911 g/cm³,Z=2; Vanadate2 also crystallizes in the monoclinic space groupP2₁/n with unit cell parameters:a=9.719(2),b=11.111(3),c=11.294(2)Å, =109.03(2)°, andD _c=1.781 g/cm³,Z=2. Each dimer contains a centro-symmetric planar four-member V₂O₂ ring with two exocyclic citrate entities coordinated by the oxygen atoms of the hydroxy-and -carboxylate ligands, while the other two -carboxylate groups remain uncomplexed. Principal dimensions of the V–O bonds are 1.986(4)_av (hydroxy) and 1.980(3)Å(-carboxyl) for vanadate1, 1.988(2)_av (hydroxy) and 1.974(3)Å(-carboxyl) for vanadate2.     

三维孔道结构(H3 NCH2 CH2 NH3)2(H3 NCH2 CH2 NH2)[VⅢ(H2O)2(VⅣ O)8(OH)4(H(P,B)O4)4((P,B)O4)4(H2O)2]·3H2O的水热合成及晶体化学研究 --(2)晶体结构与晶体化学

在单晶X射线衍射实验的基础上,对孔道结构化合物V9P8-en的类质同象物V9(P,B)8-en的晶体结构和晶体化学进行了深入研究.结果表明,该化合物的晶体学数据为:P2(1)/n,a=1.43134(9)nm,b=1.01256(6)nm,c=1.83156(12)nm,β=90.280(2)°,V=2.6545(3)nm3,Z=2,R=0.0540,wR2=0.1551.结构中,沿着三个结晶轴方向发育复杂而规整的三维孔道,最大孔径达1.83nm(∥b轴),质子化乙二胺和水分子居于孔道中.硼部分替代四面体配位的磷,替代率为B8:P8=0.1838:7.8162;其中B与{P-OH}位P的替代量大于与[P-O]位P的替代量.相对于V9P8-en来说,V9(P,B)8-en的晶胞参数发生了变化,导致b轴增长(1.0150→1.0256nm)和c轴缩短(1.8374→1.8316nm),同时β角变小(90.39→90.278(2)°).二者的化学计量比也不同,体现在结构与孔容的关系、电荷平衡、满足亲水-疏水作用的结晶水的数量及有机模板分子的赋存状态等方面都有差异.