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1.
Four new complexes RE(ABMF)2AA (RE=Sm, Eu, Tb, Dy) were synthesized by the reaction of RECl3·6H2O with acrylic acid (HAA) and 1-(2-furyl)-3-phenyl-1,3-propanedione (ABMF). The copolymerization of the rare earth complexes with methyl methacrylate was studied by using 2,2-azobis-isobutyronitrile as an initiator. The composition and structure of the four complexes were characterized by elemental analysis, UV-vis and FTIR. The glass transition temperature and molecular weight of the copolymers were determined. Photoluminescent measurement showed that ligand ABMF could efficiently transfer the energy to Sm3+ and Eu3+ ions in the complexes and sensitize the luminescence of the rare earth ions, but could not sensitize Tb3+ and Dy3+ ions. As a result, both Sm3+ and Eu3+ complexes emitted the characteristic fluorescence of Sm3+ and Eu3+ ions due to the f-f transitions. The four copolymers could emit strong fluorescence of the rare earth ions.  相似文献   

2.
The tide new compounds with chemical formula RE CuBi2 were synthesized by arc melting method followed by annealing. The crystal structures refined using Rietveld method and X-ray powder diffraction data show to be isotypic to CaMnBi2 structure type with space group P4/nmm (No. 129). The unit cell parameters are a=0.457946(4)nm,c =0. 98858(2) nm, V =0. 207319(8) nm^3 for LaCuBi2, a = 0.449279(9) nm, c = 0. 95958(4) nm, V = 0. 19369(2) nm^3 for GdCuBi2 and a =0. 447680(7) nm, c =0. 95124( 3 ) nm, V = 0. 190644(5 )nm^3 for DyCuBi2 respectively, showing lanthanide contraction. The structure is characterized by layers of edge-shearing CuBi4 tetrahedron and covalently bonded Bi square net separated by rare earth atoms.  相似文献   

3.
Synthesis and Thermal Decomposition Mechanism of Rare Earth Benzoates   总被引:1,自引:0,他引:1  
Rareearthbenzoatesareakind0fstablecompounds.Theco0rdinationcomP0undsf0rmedbyrareearthandcarboxylicacidshaveunusualstructuresandinterestinglundnesceniProperties.Bymeansoff0rmingc0njugaedcomplexes,rareearthmetalsandcarb0xylicacidscanf0rmnetorlayerp0lymerandchangetheirlundnescentprop-erties.S0merareearthcomplexeshavebeenap-Pliedinagricultureaslight-transfeedngmaeri-al8-Althoughthermaldecompositi0nmechanismofrareearthbenz0ateshasbeenreported,itdealswith0nlys0lidphaseproducts["'1,litdeab0utgasPha…  相似文献   

4.
Theintermetalliccompoundswithtransitionalbondingfeaturesoftenhaveverycomplexcrystalstructuresanduniquephysicalandchemicalproperties.Owingtotheirpartialdirectionalandpartialsaturationalfeaturesofthebonds,thevalenceruleandtherulesformetalliccompounds…  相似文献   

5.
Two series of solid complexes of europium and terbium with biphenyl 4-carboxylic acid and phen were synthesized and characterized in this report. Their elemental analysis, molar conductivities and TG-DTA studies indicate that the complexes have the composition of Eu(phen)L3·1/2H2O, Eu0.5RE0.5(phen)L3·1/2H2O; Tb(phen)L3·H2O and Tb0.5RE0.5(Phen)L3·1/2H2O. (RE=Y3 , La3 and Gd3 ; L=biphenyl 4-carboxylic acid; phen=o-Phenanthroline). The studies of their IR, UV 1H NMR and molar conductivities demonstrate that biphenyl 4-carboylic acid is bounded with RE(Ⅲ) ion. Rare earth ions coordinate with two nitrogen atoms of phen molecules directly in these rare earth complexes. The fluorescence spectra and fluorescence lifetimes of the rare earth complexes show that the fluorescent intensity and lifetime of a series of europium complexes are longer than those of the series of terbium complexes as having the some ligands. There are better fluorescent intensity and lifetime of hetero-nuclear rare earth complexes than homo-nuclear rare earth complexes for europium complexes. The fluorescence emission intensity of Eu3 is raised by inert fluorescent rare earth ions (Y3 , Gd3 and La3 ), but in Tb3 hetero-nuclear rare earth complexes the intensity of Tb3 ions are quenched by the inert fluorescent rare earth ions.  相似文献   

6.
Anisotropic structures, nanoneedles, and nanospindles of rare earth hydroxychloride (RE(OH)2Cl) and oxychloride (REOCl) (rare earth=Eu and Tb) were synthesized. The rare earth hydroxychloride nanostructures were formed via a thermally assisted hydrolysis of the rare-earth sesquioxide nanocrystals. The morphological evolution of the nanostructures was studied using high-resolution transmission electron microscopy and scanning electron microscopy, while the structural evolution was investigated using X-ray diffraction techniques. The thermal stability of the rare earth hydroxychlorides was investigated using thermogravimetric analysis. The rare earth oxychloride nanospindles were synthesized via a simple heat-treatment of rare earth hydroxychloride nanospindles.  相似文献   

7.
The electronic structure and atomic magnetic moments of clusters NdFe6, NdFe6N3 and Fe8 with a dumbbell atom-pair in rare earth-transition element compounds NdEFe17Nx(x=0, 3) were studied by spin-polarized MS-Xα method. The results are as follows: There are three negative exchange couplings between Fe(c) and Fe(f) atoms in Nd2Fe17, which occur at their odd parity orbitals. Compared to the results of α-Fe calculated by the MS-Xα method, the low Curie temperature of compounds RE2Fe17 can be explained satisfactorily. (2) There is only one weaker negative exchange coupling orbital leaving in between Fe(c) and Fe(f) sites in Nd2Fe17N3. These results may be helpful for understanding the effect of interstitial atom M(M=N, H or C) in Fe2Fe17Mx on Curie temperature. The other key factors affecting the Fe-Fe exchange coupling in Fe2Fe17 compounds were also discussed.  相似文献   

8.
Degraded chitosan, with highly water-solubility, was obtained by the oxidation of chitosan with H2O2, and then reacted with furrural. The final product coordinated with the rare earth ions (RE^3+ = Sm^3+, Eu^3+), which led to the formation of the complexes. The prepared complexes were characterized with Infrared Spectroscopy (IR), Ultra Violet (UV), fluorescence, X-Ray Diffraction (XRD), and Thermogravimetric-Differential Scanning Calorimetry (TG-DSC) measurements.  相似文献   

9.
刘睦清  高忆慈 《稀土》2006,27(5):15-19
合成了2,3-二氯异丁酸根和4-甲基吡啶氮氧化物稀土三元配合物(RE=La、Ce、Pr、Nd、Sm、Eu).通过元素分析、红外、紫外、荧光、X射线粉末衍射、XPS、热分析以及摩尔电导等分析手段,确定了配合物的组成为[REL3(4-picNO)H2O](L= CH3C2H2Cl2COO -),并对它们的性质进行了讨论.  相似文献   

10.
合成了两种纯度分别是 99.2 4%和 98.2 0 %的单晶稀土脯氨酸高氯酸盐配合物 [Pr2 (Pro) 6 (H2 O) 4](Cl O4) 6 和 [Er2 (Pro) 6 (H2 O) 4](Cl O4) 6 ,对该配合物进行了热容、热重、差热和标准燃烧热等测定。在 78~ 370 K温度区 ,用高精密全自动绝热量热仪测定了热容值 ,计算机拟合得其热容对温度的多项式方程分别为 :Cp=140 7.0 8 75 1.6 7X 170 .17X2 89.5 9X3- 76 .11X4和 Cp=1317.99 6 33.0 5 X 16 3.82 X2 15 0 .2 3X3- 86 .2 1X4,[Er2(Pro) 6 (H2 O) 4](Cl O4) 6 的 Cp- T曲线有一熔化峰 ,计算熔点为 35 5 .5 5 K,熔化熵为 6 9.5 42 J/(K m ol) ,熔化焓为2 472 5 .81J/m ol。 TG、DTA技术研究了其热分解过程 ,初步分析了配合物的分解机理。燃烧热实验给出了它们的标准燃烧热分别为 1772 0 .41k J/mol和 1810 1.6 5 k J/m ol  相似文献   

11.
The precursors RE (HSal) 3 ( RE = La, Y, Gd; HSal = C6 H4 (OH) COO) were synthesized by the rheological phase reaction method. The mechanism and products of thermal decomposition of precursors was studied by using TG,DTA, gas chromatography-mass spectrometry (GC-MS). Nano-sized RE2O3 ( RE = La, Y and Gd) power were obtained by thermal decomposition of the precursors in air at 800 ℃. TEM measurement indicates that RE2O3 are spherical particles. The middle level diameter ( d50 ) of the particles are 19.3 ( La2O3 ) , 53.8 ( Y2O3 ) and 28.6 nm( Gd2O3 ) respectively by means of laser particles size analyzer.  相似文献   

12.
Seven new rare earth transition metal sulfates were synthesized by hydrothermal reactions under conditions slightly above the critical point of water. Their crystal structures were determined from single crystal X-ray data. The compositions of the new compounds can be represented by two general formulae : REM (OH) 3 (SO4) and RE2M (OH) 3 (SO4) 2F (H2O) with RE = Gd, Tb, Dy ; M = Ni, Cu. Three different crystal structure types were found for the formula REM (OH) 3 (SO4). The structures of the new compounds all feature infinite chains of REOn coordination polyhedra, which are connected to chains of CuO6 or NiO6 octabedra. The limited size range of the rare earth cations observed in these compounds is most likely because of interactions between the octabedral chains and the chains of REOn polyhedra. The new compounds are closely related to the known yttrium transition metal sulfates.  相似文献   

13.
The present study has been conducted to contribute, once and for all, filling the lack of structural information for the whole class of rare earth (RE) carbonates owning the tengerite-(Y) structure. A complete structural characterization, carried out by Rietveld refinement of X-ray powder diffraction (XRD) data, was comparatively performed for the first time on several hydrated RE carbonates, having the general chemical formula RE2(CO3)3·xH2O, RE = Y, Gd, Tb, Dy, Ho and Er. All samples share the same space group and lattice parameters similar to tengerite-(Y); the structures are also closely related, consisting in all cases of a three-dimensional framework of nine-fold coordinated RE atom polyhedral, linked together by carbonate ions. In addition to relatively minor changes in fractional coordinates of atom sites and corresponding interatomic distances, the only perceivable difference lies in the lattice parameters affected by the ionic radius of RE3+. However, in the case of Er, which has the lowest cationic radius among the analyzed RE, the stabilization of tengerite structure is at its limit condition, because the carbonate groups are heavily distorted. Furthermore, FT-IR and Raman spectra confirm the main structural features obtained by Rietveld refinements. The observed morphology of the various samples is almost the same, being characterized by the presence of bidimensional rod-like particles grouped in agglomerates, typical of tengerite crystals, thus indicating that the crystallization mechanism occurring during the hydrothermal synthesis is the same, irrespective of the involved RE cation.  相似文献   

14.
程娟  汪仕元  雍志华 《稀有金属》2003,27(4):507-509
用不同比例的Fe和Ni部分代替WC-8Co合金中的粘结剂Co,再添加微量的碳粉和稀土氧化物Y2O3制得WC-8(Fe,Co,Ni)RE硬质合金,测试了其物理机械性能,研究了粘结剂各种成分及烧结温度、烧结气氛对硬质合金性能的影响。在一定的烧结工艺下,以Fe和Ni部分代替Co所制得的WC-8(Fe,Co,Ni)RE硬质合金,其性能可以达到甚至超过YG8的标准,同时对影响WC-8(Fe,Co,Ni)RE硬质合金性能的一些因素进行了讨论。  相似文献   

15.
The composite TiO2 films containing the mineral tourmaline particles and rare earth elements (T/RE/TiO2 )were prepared by a sol-gel method using Ti( OC4H9 )4 as raw material. The microstructure and forming mechanism of T/RE/TiO2 films were studied by scanning electron microscope (SEM). Effects of tourmaline on the photocatalytic activities of RE/TiO2 were determined by photocatalytic degradation of formaldehyde. The results show that the photocatalytic degradation ratio of formaldehyde increases by 44.2% with the composite films of Ce/TiO2 containing 0.04%tourmaline, more than that with the thin films of Ce/TiO2 under UV irradiation.  相似文献   

16.
Forthepasttenyears,thespinelLiMn2O4hasbeenstudiedextensivelyasapositiveelectrodematerialsforrechargeablelithiumandlithiumioncells,becausetheyarecheaper,lesstoxicandmoreeasilypreparedthanothercandidatesLiCoO2andLiNiO2.Unfortunately,itspracticalapplication…  相似文献   

17.
A series of Mg2-xNdxNi (x =0.05, 0.1, 0.2, 0.3) alloys and Mg1.95RE0.05Ni (RE= La, Ce, Pr, Nd, Y)ternary alloys were prepared by ball milling of mixted powder of Mg, Ni, RE and sintering under the protection of argon. XRD analysis shows that Mg2-xNdxNi (x = 0.05, 0.1 ) and Mg1.95RE0.05Ni consist of single phase with the same crystal structure as Mg2Ni. While three-phase alloys including Mg2Ni, NdNi and NdMgNi4 were formed in Mg1.8Nd0.2Ni and Mg1.7Nd0.3Ni alloys respectively. The lattice constants of Mg2Ni in those ternary alloys were calculated. The decomposition of Mg2Ni occurs in the milling process of Mg2Ni and Mg1.95RE0.05Ni alloys respectively. For the latter, another earlier reaction occurs in milling process, which means that atoms of RE are separated from crystal structure of Mg2Ni and form relevant oxides by combination with oxygen existed in argon atmosphere.  相似文献   

18.
2 mercaptobenzothiazolewasfirstreportedbyHofmann[1 ] in 1 887.Ithasbeenusedasanacceleratorinthevulcanizationofrubberformanyyears .Todayitisstillbeingusedasamainacidicacceleratorinrubberindustry .Butithasdisadvantagesofvulcanizationreversionandeasyscorch[2 ] whe…  相似文献   

19.
RE(NO_3)_3-HNO_3-P507-kerosene extraction system(RE=La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu,Y)was studied by the response surface technique.14 models for extracting single rare earth ele-ment in a broad range of acidity and initial rare earth concentration were obtained by using the stepwiseregression method.Three-dimensional display of the response surface of the model of extracting Er~(3 )wasshowed as an example,which reveals clearly the dependence of distribution ratio upon both initial acidity and ini-tial rare earth concentration.  相似文献   

20.
Five novel ternary complexes of rare earth ions with L-Aspartic acid (Asp) and o-phenanthroline (Phen) were synthesized in ethanol aqueous solution. Their compositions were characterized by elemental analysis, molar conductance, FT-IR, Raman, UV-VIS and TG-DTA. The compositions of the complexes were confirmed to be: RE(Asp)3PhenCl3·3H2O (RE: Ce3 , Pr3 , Nd3 , Sm3 , Er3 ). The antibacterial activity test shows that all these complexes exhibit excellent antibacterial ability against Escherichia coli, Staphylococcus aureus and Candida albicans. The antimicrobial spectrum of the complexes are broad.  相似文献   

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