共查询到20条相似文献,搜索用时 15 毫秒
1.
Karolina Kazmierczak 《Journal of solid state chemistry》2011,184(5):1221-1226
The lanthanide sulphate octahydrates Ln2(SO4)3·8H2O (Ln=Ho, Tm) and the respective tetrahydrate Pr2(SO4)3·4H2O were obtained by evaporation of aqueous reaction mixtures of trivalent rare earth oxides and sulphuric acid at 300 K. Ln2(SO4)3·8H2O (Ln=Ho, Tm) crystallise in space group C2/c (Z=4, aHo=13.4421(4) Å, bHo=6.6745(2) Å, cHo=18.1642(5) Å, βHo=102.006(1) Å3 and aTm=13.4118(14) Å, bTm=6.6402(6) Å, cTm=18.1040(16) Å, βTm=101.980(8) Å3), Pr2(SO4)3·4H2O adopts space group P21/n (a=13.051(3) Å, b=7.2047(14) Å, c=13.316(3) Å, β=92.55(3) Å3). The vibrational and optical spectra of Ho2(SO4)3·8H2O and Pr2(SO4)3·4H2O are also reported. 相似文献
2.
Syntheses, crystal structures and thermal behavior of two polymorphic forms of Ce(SO4)2·4H2O are reported. The first modification, α-Ce(SO4)2·4H2O (I), crystallizes in the orthorhombic space group Fddd, with a=5.6587(1), b=12.0469(2), c=26.7201(3) Å and Z=8. The second modification, β-Ce(SO4)2·4H2O (II), crystallizes in the orthorhombic space group Pnma, with a=14.6019(2), b=11.0546(2), c=5.6340(1) Å and Z=4. In both structures, the cerium atoms have eight ligands: four water molecules and four sulfate groups. The mutual position of the ligands differs in (I) and (II), resulting in geometrical isomerism. Both these structures are built up by layers of Ce(H2O)4(SO4)2 held together by a hydrogen bonding network. The dehydration of Ce(SO4)2·4H2O is a two step (I) and one step (II) process, respectively, forming Ce(SO4)2 in both cases. During the decomposition of the anhydrous form, Ce(SO4)2, into the final product CeO2, intermediate xCeO2·yCe(SO4)2 species are formed. 相似文献
3.
Karolina Kazmierczak 《Journal of solid state chemistry》2010,183(9):2087-2094
The potassium lanthanide double sulphates KLn(SO4)2·H2O (Ln=La, Nd, Sm, Eu, Gd, Dy) were obtained by evaporation of aqueous reaction mixtures of rare earth (III) sulphates and potassium thiocyanate at 298 K. X-ray single-crystal investigations show that KLn(SO4)2·H2O (Ln=Nd, Sm, Eu, Gd, Dy) crystallise monoclinically (Ln=Sm: P21/c, Z=4, a=10.047(1), b=8.4555(1), c=10.349(1) Å, wR2=0.060, R1=0.024, 945 reflections, 125 parameters) while KLa(SO4)2·H2O adopts space group P3221 (Z=3, a=7.1490(5), c=13.2439(12) Å, wR2=0.038, R1=0.017, 695 reflections, 65 parameters). The coordination environment of the lanthanide ions in KLn(SO4)2·H2O is different in the case of the Nd/Sm/Gd and the Eu/Dy compounds, respectively. In the first case the Ln atoms are nine-fold coordinated in contrast to the latter where the Ln ions are eight-fold coordinated by oxygen atoms. The vibrational spectra of KLn(SO4)2·H2O and the UV-vis reflection spectra of KEu(SO4)2·H2O and KNd(SO4)2·H2O are also reported. 相似文献
4.
Rare-earth ammonium sulfate octahydrates of R2(SO4)3·(NH4)2SO4·8H2O (R=Pr, Nd, Sm, and Eu) were synthesized by a wet process, and the stable temperature region for the anhydrous R2(SO4)3·(NH4)2SO4 form was clarified by thermogravimetry/differential thermal analysis, infrared, Raman, and electrical conductivity measurements. Detailed characterization of these double salts demonstrated that the thermal stability of anhydrous R2(SO4)3·(NH4)2SO4 is different between the Pr, Nd salts and the Sm, Eu salts, and the thermal decomposition behavior of these salts was quite different from the previous reports. 相似文献
5.
L. Schriver-Mazzuoli J. M. Coanga A. Schriver P. Ehrenfreund 《Vibrational Spectroscopy》2002,30(2):245-257
Fourier transform infrared reflection spectroscopy (incidence angle of 5°) was used to characterize thin films of dimethyl ether (DME) and of mixtures containing water and DME between 10 and 160 K under a pressure of 10−7 mbar. Solid DME has two solid phases: an amorphous phase which is obtained below 65 K and a crystalline phase >65 K. From 90 K, DME begins to sublimate with surface binding energy of 20±2 kJ mol−1. Vibrational spectrum of DME trapped in water ice remains nearly unchanged from 30 to 120 K. Between 120 and 130 K, a large part of DME is released and strong changes in the frequencies and the profile of the absorptions of DME are observed. This behavior suggests the formation of clathrate hydrate. Below 120 K, the trapped DME is hydrogen-bonded to water molecules. 相似文献
6.
Thermolysis of Cu(NO3)2·3H2O is studied by means of XRD analysis in situ and mass spectral analysis of the gas phase at P=1/10 Pa at low heating rate. It is shown that stage I of the dehydration (40-80 °C) results in the consecutive appearance of crystalline Cu(NO3)2·2.5H2O and Cu(NO3)·H2O. Anhydrous Cu(NO3)2 formed during further dehydration at 80-110 °C is moderately sublimed at 120-150 °C. Dehydration is accompanied by thermohydrolysis, leading to the appearance of Cu2(OH)3NO3 and gaseous H2O, HNO3, NO2, and H2O. The higher pressure in the system, the larger amount of thermohydrolysis products is observed. The formation of the crystalline intermediate CuOx(NO3)y was observed by diffraction methods. Final product of thermolysis (CuO) is formed at 200-250 °C. 相似文献
7.
A cobalt phosphonate (H3O)6·[Co4(H2O)4(HPMIDA)2(PMIDA)2)]·2H2O, 1, has been synthesized from a mild solvothermal reaction of Co(II) ion with N-(phosphonomethyl)iminodiacetic acid (H4PMIDA). Compound 1 crystallizes in the triclinic space group with cell parameters of , , , α=93.06(3)°, β=99.66(3)°, γ=90.34(3)° and Z=1. Compound 1 shows a novel tetra-nuclear molecular structure. In the crystal lattice, molecules of 1 hydrogen bond to each other to form two-dimensional (2D) layers, which are further linked together by the co-crystallized H2O molecules and H3O+ counter ions through hydrogen bonding to form the 3D supramolecular network. Thermogravimetric analysis, IR spectrum, magnetic susceptibility and luminescent spectra are given. 相似文献
8.
9.
Magnus G. Johnston 《Journal of solid state chemistry》2004,177(11):4316-4324
Three new hydrated scandium selenites have been hydrothermally synthesized as single crystals and structurally and physically characterized. Sc2(SeO3)3·H2O crystallizes as a new structure type containing novel ScO7 pentagonal bipyramidal and ScO6+1 capped octahedral coordination polyhedra. Sc2(SeO3)3·3H2O contains typical ScO6 octahedra and is isostructural with its M2(SeO3)3·3H2O (M=Al, Cr, Fe, Ga) congeners. CsSc3(SeO3)4(HSeO3)2·2H2O contains near-regular ScO6 octahedra and has essentially the same structure as its indium-containing analogue. All three phases contain the expected pyramidal [SeO3]2- selenite groups. Crystal data: Sc2(SeO3)3·3H2O, Mr=524.85, trigonal, R3c (No. 161), , , , Z=6, R(F)=0.018, wR(F2)=0.036; Sc2(SeO3)3·H2O, Mr=488.82, orthorhombic, P212121 (No. 19), , , , , Z=4, R(F)=0.051, wR(F2)=0.086; CsSc3(SeO3)4(HSeO3)2·2H2O, Mr=1067.60, orthorhombic, Pnma (No. 62), , , , , Z=4, R(F)=0.035, wR(F2)=0.070. 相似文献
10.
Dirubidium calcium tetraborate octahydrate, Rb2Ca[B4O5(OH)4]2·8H2O, was prepared by reaction of Rb-borate aqueous solution with CaCl2 and it's structure has been determined by single-crystal X-ray diffraction data. It crystallizes in the orthorhombic system, space group P212121 with unit cell parameters, Z=4, The structure contains alternate layers of [B4O5(OH)4]2− polyanions separated by water molecules and Rb, Ca cations. The isolated [B4O5(OH)4]2− is constructed from two BO3(OH) tetrahedron groups and two BO2(OH) triangular groups joined at common oxygen atoms. The two BO3(OH) tetrahedron groups are further linked by means of an oxygen bridge across the ring. The Ca2+ ion displays seven coordination, while the two non-equivalent Rb+ ions display nine and seven coordination, respectively. Infrared and Raman (4000-400 cm−1) spectra of Rb2Ca[B4O5(OH)4]2·8H2O were recorded at room temperature and analyzed. Fundamental vibrational modes were identified and band assignments were made. The dehydration of this hydrated mixed borate occurs in one step and leads to an amorphous phase which undergoes a crystallization. 相似文献
11.
The thermal decomposition course of europium acetate tetrahydrate (Eu(CH3COO)3·4H2O) was probed on heating up to 1000 °C in a dynamic atmosphere of air by thermogravimetry and differential thermal analysis. The solid- and gas-phase decomposition products were identified by X-ray diffractometry, ex- and in situ infrared spectroscopy and mass spectrometry. Results obtained showed the acetate to dehydrate stepwise at 145-283 °C, and then decompose stepwise to yield eventually cubic-Eu2O3 at ≥663 °C encompassing the formation of intermediate oxycarbonate (Eu2O(CO3)2/Eu2O2(CO3) solid products (at 347-466 °C)) and H2O, (CH3)2CO and CO2 as primary gaseous products. A considerable enhancement of the production of the primary gas phase products at 400-450 °C and the emergence of (CH3)2CCH2, CH4 and CO molecules in the gas phase are ascribed to reactions occurring at the gas/solid interface at the expense of some of the primary products. These interfacial activities impart application-worthy adsorptive and catalytic functions for the associated solid products. 相似文献
12.
利用精密自动绝热热量计测定了Nd(Gly)2Cl3·3H2O在80-357K和Pr(Ala)3Cl3·3H2O在80-374K温区的热容. 根据两个化合物的热容计算出了相对于参考温度298.15K的热力学函数(HT?H298.15)和(ST?S298.15). 根据热重(TG)分析结果, 提出了这两个稀土化合物可能的热分解机理. 利用溶解-反应恒温热量计测定相关化合物的溶解焓并设计盖斯热化学循环, 计算出了两个化合物的标准摩尔生成焓. 相似文献
13.
A new coordination compound [Ni(CHZ)3]SO4·3H2O (CHZ=carbohydrazide) was synthesized and characterized by elemental analysis and fourier transform infrared (FTIR) spectra, and its crystal structure was determined by X-ray single crystal diffraction. The crystal belonged to the triclinic system, space group
with a=0.85237(1) nm, b=0.90964(1) nm, c=1.22559(2) nm, β=96.731(2)°, V=0.8849(2) nm3, Z=2, Dc=1.798 g·cm−3. In the asymmetric unit, three carbohydrazide (CHZ) bidentate ligands were coordinated with a Ni(II) cation by carbonyl O atoms and terminal N atoms of the hydrazine groups to form three planar chelate rings which were vertical to one another. Ni(II) cations, CHZ ligand molecules, sulfate anions, and lattice water molecules were jointed to a complicated three-dimensional network structure through coordination bonds, electrostatic forces and extensive hydrogen bonds. Natural bond orbital (NBO) atomic charges of CHZ were obtained from the density functional theory (DFT) method at the B3LYP/6-311+G** level to interpret the reason why the coordination sites in carbohydrazide molecule were the oxygen atom of the carbonyl group and terminal N atoms of the hydrazine group. The thermal decomposition mechanism was tested through differential scanning calorimetry (DSC), thermogravimetric analyses, and Fourier transform infrared spectra. The kinetic parameters of the two exothermic processes of the title compound were studied applying the Kissinger's and Ozawa-Doyle's methods. The results indicated that the title complex possessed high energy and good thermal stability. 相似文献
14.
[Cd(ATZ)~4(H~2O)~2](PA)~2·2H~2O的合成、晶体结构 和热分解机理研究 总被引:6,自引:0,他引:6
合成了以5-氨基四唑为配体的镉配合物[Cd(ATZ)~4(H~2O)~2](PA)~2·2H~2O,并对其进行了晶体结构测定。测定结果表明,该配合物分子具有中心对称性,每个Cd^2^+分别与2个水分子中的氧原子和4个5-氨基四唑(ATZ)分子中的4-位氮原子配位,形成六配位畸变八面体结构;在配合物分子间存在大量氢键,增加了整个晶体结构的稳定性。通过DSC和TG-DTG分析,提出了标题化合物的热分解机理。 相似文献
15.
Bei-Ping Liu Zhi-Cheng Tan Xiao-Zheng LanHua-Guang Yu Da-Shun ZhangLi-Xian Sun 《Thermochimica Acta》2003,401(2):233-238
Two solid-state coordination compounds of rare earth metals with glycin, [Gd4/3Y2/3(Gly)6(H2O)4](ClO4)6·5H2O and [ErY(Gly)6(H2O)4](ClO4)6·5H2O were synthesized. The low-temperature heat capacities of the two coordination compounds were measured with an adiabatic calorimeter over the temperature range from 78 to 376 K. [Gd4/3Y2/3(Gly)6(H2O)4](ClO4)6·5H2O melted at 342.90 K, while [ErY(Gly)6(H2O)4](ClO4)6·5H2O melted at 328.79 K. The molar enthalpy and entropy of fusion for the two coordination compounds were determined to be 18.48 kJ mol−1 and 53.9 J K−1 mol−1 for [Gd4/3Y2/3(Gly)6(H2O)4](ClO4)6·5H2O, 1.82 kJ mol−1 and 5.5 J K−1 mol−1 for [ErY(Gly)6(H2O)4](ClO4)6·5H2O, respectively. Thermal decompositions of the two coordination compounds were studied through the thermogravimetry (TG). Possible mechanisms of the decompositions are discussed. 相似文献
16.
采用溶液法合成了一个新的Tutton盐Na2[Co(H2O)6](SO4)2通过红外光谱和X-射线单晶衍射对其进行了表征.晶体结构分析表明该化合物晶体属单斜晶系,P21/c空间群,晶胞参数:a=0.6185(2)nm,b=1.2334(3)um,c=0.9137(1)nm,β=105.775(1)°,V=0.67078(2)nm3,Z=2.固体粉末紫外可见透射光谱是不连续的,具有较高的透过率和较窄的带宽(300~450 nm).用循环伏安法研究了化合物的电化学性质,发现Na2[Co(H2O)6](SO4)2掺杂氢氧化镍电极片的氧化还原峰电流均有较大提高,电极反应活性明显增加. 相似文献
17.
The kinetics of the dehydration of CsNd(SO4)2 · 4 H2O to CsNd(SO4)2 · H2O and then to CsNd(SO4)2 are studied by isothermal weight change. The reactions are phase-boundary-controlled. Reaction mechanism and activation energy depend on sample weight. 相似文献
18.
The first organically templated layered structure of scandium sulfate, (H2en)Sc2(SO4)4·(H2O)0.72, (en=ethylenediamine) was synthesized by a hydrothermal method and characterized by single crystal X-ray diffraction. In the title compound, scandium ions are bridged by sulfate groups with a ratio of 1:2 into a 436 layer structure. These layers are parallel packed and separated from each other by ethylenediammonium dications and water molecules. The title compound crystallizes in the monoclinic space group P2/c, with cell parameters , , , β=91.210(3)°, and Z=2. Refinement gave R1[I>2σ(I)]=0.0354 and wR2[I>2σ(I)]=0.0878. Thermogravimetric analysis indicates that this material is thermally stable to above 400 °C. 相似文献
19.
A complex of holmium perchlorate coordinated with l-glutamic acid, [Ho2(l-Glu)2(H2O)8](ClO4)4·H2O, was prepared with a purity of 98.96%. The compound was characterized by chemical, elemental and thermal analysis. Heat capacities of the compound were determined by automated adiabatic calorimetry from 78 to 370 K. The dehydration temperature is 350 K. The dehydration enthalpy and entropy are 16.34 kJ mol−1 and 16.67 J K−1 mol−1, respectively. The standard enthalpy of formation is −6474.6 kJ mol−1 from reaction calorimetry at 298.15 K. 相似文献
20.
Yang Zhou Yanqiang Li Qingran Ding Youchao Liu Yangxin Chen Xitao Liu Xiaoying Huang Lina Li Sangen Zhao Junhua Luo 《中国化学快报》2021,32(1):263-265
Two fluoride sulfates,K2Mn3(SO4)3F2·4H2O(Ⅰ) and Rb2Mn3(SO4)3F2·2H2O (Ⅱ) are obtained by water solution method.Single-crystal X-ray diffraction analysis indicated that they crystallize in space groups of Cmc21.Their structures feature a pseudo-KTP structure consisting of interconnecting[Mn3(SO4)3F2(H2O)2]∞ layers,which are further packing along the a axis with alkali metal cations balancing the charges.The structure relationships between the two compounds are discussed.Secondharmonic generation measurements manifest that Ⅰ and Ⅱ have similar second-harmonic generation responses of about 0.2 and 0.25 times that of KH2PO4. 相似文献