Phase Behavior and Crystal Structure of Perovskite-Type Rare Earth Complex Oxides

Several compounds of rare earth complex oxides containing manganese and titanium were synthesized in Ar, and their crystal structures were analyzed by powder X-ray diffraction data and Rietveld method. Structures of A0.67Ln0.33 Mn0.33Ti0.6703（A = Ca or Sr and Ln = rare earth） were found to have orthorhombic symmetry with the space group Pnrna, and their interatomic distances and bond angles were obtained. This space group was also derived from electron microscopic study. Electrical conductivity of Cao.67Ln0.33Mn0.33Ti0.6703 for several rare earth elements showed a semiconducting property with the activation energy of 0.4 eV. Some of these compounds of the strontium system show the antiferromagnetic properties below 10 K.

Syntheses,Crystal Structures and Kinetic Mechanisms of Thermal Decomposition of Rare Earth Complexes with Schiff Base Derived from o-Vanillin and p-Toluidine

Three complexes, [Pr（NO3）3（HL）2] （1）, [Nd（NO3）3（HL）2] （2） and [Er（NO3）3（HL）2] ·0.5H2O （3）, were synthesized from the reaction of a Schiff base ligand 2-[ （4-methylphenylimino）methyl ]-6-methoxyphenol （C15 H15 NO2, HL） with Ln（NO3）3·6H2O （Ln = Pr, Nd, Er）. Characterization by single-crystal X-ray diffraction technique, elemental analysis, molar conductance, FT-IR, UV-Vis, ^1H NMR and thermal analysis shows the title complexes are neutral molecules where the central Ln（ Ⅲ） ion is ten-coordinated in biapical anti-hexahedron prism geometry, with four oxygen atoms of the phenolic hydroxy and methoxy groups in the two bidentate Schiff base ligands and six oxygen atoms provided by the three bidentate NO3 - anions. Additionally, the kinetic mechanism of thermal decomposition of complex 3 was determined with a TG-DTG curves by both integral and differential methods. The functions of thermal decomposition reaction mechanism and the equation of kinetic compensation effect were obtained.

Synthesis and crystal structure of a 1D chainlike rare earth coordinated tungstogermenate:[(CH_3)_4N]_(1.50)H_(3.50)[Gd(GeW_(11)O_(39))(H_2O)_2]·2.5H_2O

AID zigzag polyoxometalate [（CH3）4N]1.50H3.50[Gd（GeW11O39）（H2O）2]·2.5H2O （1） was synthesized by reaction of the monova- cant polyanion [α-GeW11O39]^8- with Gd^3＋ ions in aqueous solution and characterized by IR, UV spectra, ICP, and X-ray crystallography. X-ray single-crystal structural analysis indicated that the title compound crystallized in a monoclinic lattice, C2/c space group with α= 2.8201（5）, b=2.2885（3）, c=2.4033（4） nm, β=123.875 （2）°, V=12.878（4） nm3, Z=8, R1=0.0623, wR2=0.1287. The solid-state structure of the title compound displayed an infinite one-dimensional arrangement built up of [α-GeW11O39]^8- polyanions connected by Gd^Ⅲ cations.

Syntheses aod Crystal Structures of Rare Earth Complexes with Adamantanecarboxylic Acid, [LnL_3(HL)(H_2O)]_2·2EtOH·2H_2O (Ln=Nd (1), La (2))

The title complexes （LnL3 （HL） （H2O） ]2· 2EtOH·2H2O （Ln= Nd （1）, La （2）, HL=adamantanecarboxylic acid） were prepared and determined by single-crystal X-ray diffraction. Both complexes crystallize in triclinic system with space group P 1^-, cell parameters are： complex （1） a = 1.0556（2） nm, b =1.4913（3） nm, c = 1.4920（3） nm, a = 106.26 （3）°, β=93.51（3）°, γ=97.23（3）°, V=2.2253 （5） nm^3, Dcal=1.409 g · cm^-3, Z = I , F （ 000 ） = 990, μ（Mo Kα） = 1. 225 mm^-1, M, = 1884.50; complex （2） a = 1.0453（2） nm, b = 1.4971（3）nm, c = 1.5052（3） nm, α = 106.07（3）°, β =93.58 （3）°, γ=97.56（3）°, V=2.2391（5）nm^3, Dcal= 1.397 g·cm^-3, Z = 1, F（000） =984, μ（Mo Kα） = 1.015 mm^-1, Mr= 1877.88. The final R and wR are 0. 0396 and 0. 1062 for 8589 （1 ≥ 2σ （I）） observed reflections for complex （1）, 0.0505 and 0. 1344 for 8417 （ 1 ≥ 2σ （1） ） observed reflections for complex （2）, respectively. The crystals are consisted of a binuelear molecule. The coordination geometry of the Ln（ Ⅲ ） ion can be described as trieapped trigonal prism.

THE CRYSTAL STRUCTURE OF RARE EARTH COMPLEX WITH AMINO ACIDS Ⅱ The Crystal Structure of Gtutamate Comptex of Erbium Perchtorate

The crystat structure of {[Er;（L—Glu）;（H;O）;]（ClO;）;·3H;O);has been studied by X-ray diffraction. The crystal is monoctinic with space group P2;and cell parameters a=19.987（3） , b=16.505（3） , c=11.040（2） , β=104.69（1）;, V=3538（1） , Z=2, Dc=2.29 g. cm;, μ=53.2 cm;, F（000）=2384. The asymmetric unit contains two complex motecules and four centre ions. Each erbium （Ⅲ） is coordinated by five oxygen donors from four different glutamates and four oxygen donors from the aqua ligand to form a nine coordination potyhedron. The mean distances of Er—0 （carboxylate） and Er—Ow are 2.439 and 2.41 respectivety. The finat R and Rw are 0.043 and 0. 058, respectivety.

Synthesis, Crystal Structure and Characterization of a One-dimensional Supramolecular Rare Earth Complex of N-(6-(4-Methylpyridinyl))ketoacetamide

A one-dimensional （1D） supramolecular rare earth complex [Nd（NO3）2L2-（C3H6O）][NdL（NO3）4]} （L=N-（6-（4-methylpyridinyl））ketoacetamide） has been prepared and characterized by elemental analysis, IR and electronic spectroscopy, and single-crystal X-ray diffraction. The crystal crystallizes in the triclinic system, space group P1^- with a=0.9146（6）, b=1.2581（8）, c=2.2316（14） nm, α=99.352（10）,β=97.209（9）, γ=103.935（9）°, V=2.422（3） nm3, Dc=1.776 g/cm^3, C33H42N12Nd2O25, Mr=1295.27, Z=2, F（000）=1288, μ=2.217 mm-1, R=0.0508and wR=0.1046 for 5173 observed reflections （I 〉 2σ（I））. In the structure of the title complex,one-dimensional supramolecular double-chains are formed by intermolecular hydrogen bonding interactions.

Layer Structure Analysis of Low-Carbon Steel Containing Rare Earth by High-Temperature Carburizing of Liquid Cast-Iron

The layer structure of low-carbon steel containing RE by high-temperature (T>1200 ℃) carburizing of liquid cast-iron was studied and the diffusion activation energy of carbon was calculated by metallographic microscpe, chemical analysis etc. The result shows that the technology of carburizing in liquid cast-iron can expedite caburization distinctly and changes the carburizing layer structure. The carburizing rate is 60～80 times of that of the traditional technology, and there is about 43% decrease in the activation energy compared with gas-carburization. In outer structure layer, cementite is formed simultaneously both on the crystal boundary reticularly and inside the crystal grains stripedly. In inner carburizing layer, there is undissolved blocky ferrite in reticular cementite. Besides, rare earth element can expedite carburization process.

Phase Behavior of BaLn_2Mn_2O_7 (Ln=Rare Earth) with a Layered Perovskite Structure

Many phases appear in BaLn 2Mn 2O 7 family (Ln=rare earth) belonging to one of the Ruddlesden-Popper type compounds, depending upon the experimental conditions such as heating conditions when prepared and composition. Some of these phases were characterized by powder X-ray diffraction method using Rietveld analysis. These phases have only a little difference in crystal structure which has fundamentally K 2NiF 4 type structure, although the X-ray diffraction patterns are clearly different: a little deformation or tilting of the oxygen octahedron surrounding a central manganese ion composing the main frame of this structure induce these different diffraction patterns. Phase behavior of these compounds, mainly the detailed relation between various phases in BaTb 2Mn 2O 7, was refined including the data of high temperature X-ray diffractometry.

Synthesis and Structures of A Series of Novel Rare Earth Transition Metal Sulfates

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.

Synthesis, Structure and Luminescent Properties of Three 1D Chain Rare Earth Complexes

Three 1 D chain coordination polymers [Ln(pydc)2(H2 O)2]n·n Him(Ln = Dy(1), Gd(2), Sm(3), H2 pydc = pyridine-2,5-dicarboxylic acid, Im = imidazole), were solvothermally synthesized by the reaction of pyridine-2,5-dicarboxylic acid(H2 pydc), Ln(Ⅲ) salts and imidazole. They have been characterized by X-ray single-crystal diffraction, IR spectra, TGA analysis and elemental analysis. Structural analyses revealed that complexes 1~3 have similar 1 D chain structures and belong to P1 space group. It is noteworthy that complexes 1~3 exhibited excellent thermal stability and no weightlessness below 117 ℃. Meanwhile, 1 and 3 show characteristic fluorescence of corresponding lanthanide metal ions in solid state at room temperature.

Modifying Behaviors of Ultrasonic Irradiation and Rare Earth Metal Cerium on Electroless Co-Ni-B Alloy Coating

By plasma transmitting spectrograph,electron energy spectrometry,X-ray diffractometry,transmission electron microscopy and micro-hardometry,the effects of ultrasonic irradiation and rare earth metal cerium on the depositing speed,chemical composition,crystal structure and microhardness of electroless Co-Ni-B alloy coating were inspected and analyzed. The results show that cerium and ultrasonic irradiation can evidently raise the depositing speed of electroless Co-Ni-B alloy. The cerium content of electroless Co-Ni-B-Ce alloy coating also increases after ultrasonic irradiation applied to electroless Co-Ni-B plating process. Under the action of ultrasonic irradiation and rare metal cerium,the chemical composition of electroless Co-Ni-B alloy coating is changed. Electroless Co-Ni-B alloy with amorphous structure is transformed to electroless Co-Ni-B-Ce alloy with microcrystalline in general state and electroless Co-Ni-B-Ce alloy with crystalline structure in ultrasonic irradiation. In this way microhardness of the coatings increases remarkably.

Theoretical elucidation of rare earth extraction and separation by diglycolamides from crystal structures and DFT simulations

Diglycolamides(DGAs) show excellent application prospects for the extraction and separation of rare earth metals from highly radioactive liquid wastes and rare earth ores.The extraction ability of DGAs for rare earth ions in nitrate or chloride media increases with increasing atomic number of the rare earth metal.To understand the origin of this phenomenon,three binuclear crystals [Ln(TEDGA)_(3)][Ln(NO_(3))_(6)] of N,N,N’,N’-tetraethyldiglycolamide(TEDGA) with rare earth ions La(Ⅲ),Pr(Ⅲ) and Eu(III) were prepared and characterized crystallographically.The three complexes belong to the triclinic crystal system,P-1 space group.The bond lengths of Ln-O_(amide) are significantly shorter than those of Ln-O_(ether) in the same crystal.The Ln-O_(amide) and Ln-O_(enher) bond lengths gradually decrease with increasing atomic number of the rare earth ion.The dihedral angle formed by TEDGA and metal ions through the tridentate coordination gradually increases with increasing metal ion atomic number,tending toward the formation of sizeable planar coordination structures for the most massive rare earth ions.The structures of the compounds formed by the extractant and metal ion were optimized by means of DFT simulations.We find that the interaction between TEDGA and the rare earth ion is dominated by electrostatic interaction by analyzing binding energy,WBIs,Mulliken charge,natural electron configurations,and molecular orbital interaction.The covalent component of the Ln-O bonds of the complexes increases with increasing metal atomic number.The observed increase in extraction and separation capacity of diglycolamides for rare earth ions with increasing atomic number might be due to the formation of two fivemember rings by one tridentate ligand.The rare earth ions with large atomic numbers tend to form planar structures with large dihedral angles with DGA ligands.

Synthesis and Crystal Structure of Rare Earth Metal Chlorides Bearing Bridged-lndenyl Ancillary Ligand

Two new rare earth metal chloride complexes supported by a bridged-indenyl ancillary ligand, [C9H6SiMe2- （CH2）2SiMeEC9H6]Ln（u-Cl）2Li（TMEDA） [Ln=Y （1）, Lu （2）], were synthesized via salt metathesis reaction. Reaction of C9H7SiMeE（CH2）ESiMeEC9H7 with 2 equiv, of n-butyllithium in hexane at room temperature afforded [C9H6SiMe2- （CHE）2SiMeEC9H6]Li2 as white powder in 95% isolated yield. Further treatment of [C9H6SiMe2（CHE）2SiMeE- C9H6]Li2 with anhydrous LnCl3 in 1 ： 1 molar ratio in THF/TMEDA at room temperature provided the bridged-indenyl rare earth metal chlorides 1 and 2 in 86%--89% isolated yields. Both complexes were characterized by FT-IR spectroscopy, NMR spectroscopy, elemental analysis, and X-ray single crystal structure analysis. The central metals in both complexes are eight-coordinated by two indenyl ligands in η^5-fashion, and two chlorine atoms to adopt a distorted tetrahedral geometry.

Effect of rare earth(Nd^(3+))metal doping on structural,morphological,optical and magnetic traits of Zn-Mg nano-ferrites

Herein,we report the synthesis of Zn_(0.7)Mg_(0.3)Nd_(x)Fe_(2-x)O_(4)(where,x=0,0,0,01,0,02)ferrite nanoparticles by employing the sol-gel auto-combustion technique.The X-ray diffraction(XRD)pattern suggests the formation of a pure cubic structure,without any impurity phase,with an Fd3m space group at room temperature.With increasing doping amount,the crystallite size is reported as 35-41 nm,while the lattice parameters rise from 0.8381 to 0.8395 nm.Field emission scanning electron microscopy(FESEM)images show the formation of spherical grains with agglomerated morphology in all the samples,with grain sizes ranging from 49 to 103 nm.Energy dispersive X-ray spectroscopy(EDX)and elemental mapping investigation confirm the chemical purity of all the samples.Fourier transform infrared(FTIR)analysis shows the presence of two prominent peaks around 440 and 560 cm^(-1)that correspond to the octahedral and tetrahedral positions.In addition,the existence of five Raman active vibratio nal modes in all produced specimens again confirms the structural purity of all the samples.The M-H curve shows that saturation magnetization(M_(s))first increases from 14.98 to 28.22 emu/g and then decreases to 18.98emu/g with increasing doping amount.This is due to the A-B type super-exchange interaction for the synthesized samples.The variation in coercivity(H_(c))and magnetic anisotropy(K_(1))suggest the thermal stability of all the samples and can be utilized in transformers and solenoids.

Preparation and Crystal Structure of a Rare-earth Salt Based on the Decavanadate (V_(10)O_(28)^(6-)): [Y(H_2O)_8]_2[V_(10)O_(28)]·9H_2O

The salt, [Y（H2O）8]2[V10O28]·9H2O, contains two discrete water-groups coordinated Y（Ⅲ） cations, an isopoly complex ion, decavanadate （V10O28^6-） and nine additional water molecules, which are combined together by static electric forces and hydrogen bonds. The y^3＋ is eight-coordinated with a square antiprism geometry. The single-crystal X-ray analysis reveals that the crystal crystallizes in triclinic, space group P1^- with a = 9.1454 （18）, b = 10.007（2）, c = 12.772（3） A°, α= 68.86（3）, β = 77.50（3）, γ= 89.23（3）°, V= 1061.7（4）A°^3 and Z= 1.

Crystal structure and infrared spectrum of thallium holmium polyphosphate, TlHo(PO_3)_4

Crystals of thallium-holmium polyphosphate T1Ho（PO3）4 were grown by flux method technique and characterized by single crystal X-ray diffraction. Structure of T1Ho（PO3）4 was solved for the first time, and it crystallized in the monoclinic P21/n space group with the following unit-cell dimensions： a=1.02225（3） nm, b=0.88536（2） nm, c=1.09541（4） nm, β=105.888（1）°, V=0.95354（5） nm^3 and Z=4. The crystal structure was solved from 2174 independent reflections with final R1（F^2）=0.0442 and Rw（F^2）=0.0861 refined with 164 parameters. The atomic arrangement could be described as a long chain polyphosphate organization. Holmium atoms had eightfold coordination. The structure of T1Ho（PO3）4 consisted of HoO8 polyhedra sharing oxygen atoms with phosphoric group PO4. Infrared spectrum was investigated at room temperature in the frequencies range, 350--4000 cm^-1, showing some characteristic vibration bands of infinite chain structure of PO4 tetrahedra linked by bridging oxygen.

Synthesis，Crystal Structure and Infrared Spectrum of Lanthanum Dinuclear Coordination Compound with Alanine：〔La2（ala）4（H2O）8〕·（ClO4）6

Lanthanum coordination compound with l-alanine[La2（ala）4（H2O）8]·（ClO4）6（ala=l-alanine） was synthesized by reaction of lanthanum perchlorate with l-alanine in aqueous solution and obtained in the form of single crystals.The X-ray crystal structure has been determined and the IR spectrum has been studied.The title compound Cl6La2C12H44O40N4,Mr=1375.2,crystallizes in the triclinic,space group P1 , with parameters: a= 11.227（3）,b=11.445（2）,c=11.014（3）,α=114.46（2）,β=114.51（2）,γ=78.62（2）°,V=1171.73,Z=1,Dc=1.95 g/cm￣3,F（000）=680,μ=22.9 cm￣-1（MoKα）.The final R=0.050,Rω=0.051.In the crystal,two lanthanum ions are coordinated by four alanine molecules via four carboxylate bridges to form a dinuclear coordination compound.Four water molecules are coordinated to each lanthanum ion. There is a symmetric centre between the two lanthanum ions.The IR spectrum of the coordination compound and the relationship between the IR spectrum and the structure have been studied.The mechanism of the configuration inversion of alanine has been proposed.

Synthesis, Crystal Structure and Magnetic Behaviour of Three Dimensional Iron-Cerium Cyanide Bridged Bimetallic Assembly

The complex with the formula [CeFe(CN)(6)(H2O)(3)]. 2H(2)O was synthesized and structurally characterized. It crystallizes in hexagonal, space group P3, a = 0.75320(10) nm, b = 0.75320(10) nm, c = 1.4374(3) nm, gamma = 120 degrees, V = 0.7062(2) nm(3), Z = 3, Be = 3.048 Mg .m(-3), F(000) = 606, mu = 6.346 mm(-1), T = 293(2) K, R-1 = 0.0169, wR(2) = 0.0459. The structure is a three-dimensional network containing open channels formed by the nine-coordinated CeN6(H2O)(3) groups and octahedral FeC6 groups through the cyanide linkages. Magnetic susceptibility measurements in the temperature range of 5.1 similar to 300 It show an antiferromagnetic interaction between the Ce3+ and Fe3+ ions.

Influence of rare earth ion substitutions on the structural,optical,transport,dielectric,and magnetic properties of superparamagnetic iron oxide nanoparticles

Superparamgnetic Fe_3O_4 and RE:Fe_3O_4(RE=Dy,Nd,La)nanoparticles with an average crystallite size in the range of 15–24 nm,were synthesized by co-precipitation method.The samples were characterized using X-ray diffraction(XRD),scanning electron microscopy(SEM),vibrating sample magnetometer(VSM),UV–Vis spectroscopy,LCR bridge,and two-probe technique.X-ray diffraction patterns of all the investigated samples reveal the typical phase of magnetite structure,with a small contribution of orthoferrite(NdFeO_3)as a secondary phase in Nd:Fe_3O_4 sample.The saturation magnetization(M_s)of the samples has values in the range from 41.8 to 52.3 emu/g,and decreases with RE ion doping depending on the ionic radius.Negligible values of the coercivity H_c and remanenceM_r,indicate the superparamagnetic nature of the investigated samples.The calculated values of indirect optical band gap of Fe_3O_4 and RE:Fe_3O_4 nanoparticles are in the range of0.9–1.25 eV.The dielectric constant of the samples decreases,while their activation energy increases with the increasing of ionic radii of dopants.

Structure and Properties of a New Rare-earth Borate LiSrY_2(BO_3)_3

The structure of LiSrY2（BO3）3 has been solved by single-crystal X-ray diffraction analysis at 298 and 113 K on different diffractometers.It crystallizes in trigonal with space group P-3m1（No.164）.The cell parameters at room temperature are as follows：a = 10.3345（9）,c = 6.4049（11） ,V = 592.41（13） 3,Z = 3,Mr = 448.81,F（000） = 618,μ = 21.327 mm-1 and Dc = 3.774 g/cm3.The crystal structure consists of gear-like [BY6O33] groups which are linked together by corner-sharing to form a two-dimensional layer parallel to the ab plane.These layers are connected one after another by sharing oxygen atoms with B（2） atoms along the c direction to construct a three-dimensional framework.Li and Sr atoms just occupy the cavities formed by oxygen atoms.In addition,the vibrational spectroscopy of LiSrY2（BO3）3 and photoluminescence properties of the Eu3＋ doped LiSrY2（BO3）3 were also studied.