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1.
Bie H  Mar A 《Inorganic chemistry》2008,47(15):6763-6770
The isostructural rare-earth titanium antimonides RE 2Ti 11 - x Sb 14 + x ( RE = Sm, Gd, Tb, Yb) have been synthesized by arc-melting reactions of the elements. Single-crystal X-ray diffraction revealed that they adopt a new structure type (Pearson symbol oP54, space group Pnma, Z = 2; a = 15.8865(6)-15.9529(9) A, b = 5.7164(2)-5.7135(3) A, c = 12.9244(5)-12.9442(7) A for RE = Sm-Yb). The structure consists of titanium-centered octahedra (CN6) and pentagonal bipyramids (CN7) connected to form a 3D framework whose cavities are filled with RE atoms. 1D linear skewers of titanium atoms, within face-sharing octahedral chains, and similar skewers of antimony atoms, associated with the titanium-centered pentagonal bipyramids, extend along the b direction. On proceeding from Sm 2Ti 11Sb 14 to Tb 2Ti 10.41(1)Sb 14.59(1) and Yb 2Ti 10.58(1)Sb 14.42(1), antimony atoms are disordered within some of the titanium sites. Resistivity measurements on the samarium and ytterbium members indicated metallic behavior.  相似文献   

2.
Piao S  Lidin S 《Inorganic chemistry》2007,46(16):6452-6463
A series of binary quasicrystal approximants RE13Zn58+delta (RE = Ho, Er, Tm, and Lu) have been prepared, and structural studies were performed by means of single-crystal X-ray diffraction. All four compounds crystallize in the orthorhombic system, but while the Ho-containing compound crystallizes in space group Pcmn, the rest of the compounds crystallize in Pc21n. This work is a continuation of the structural studies on RE13Zn approximately 58 (RE = Ce, Pr, Nd, Sm, Gd, Tb, and Dy), which all belong to the hexagonal system. The sequence of RE13Zn58+delta compounds exhibits a large variability in local ordering and composition, and therefore the crystal structures are generally rather more complex than those previously reported and exhibit a number of different ordering modes. These four compounds are structurally closely related to each other.  相似文献   

3.
彭周人  李一志  王流芳 《化学学报》1990,48(10):939-945
本文首次报道合成了稀土-腺苷三磷酸固态配合物RE(III)-ATP)RE=Y、La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu)。运用红外、激光raman、热分析、紫外、顺磁、X射线衍射、元素分析、配位滴定等技术测定了上述配合物的化学组成和分子结构, 其分子式用通式表为[RE(III)(HATP)(H2O)4]。采用量子化学INDO方法计算了系列物的电子结构, 依据计算结果讨论了生物化学中高能磷酸键的本质。  相似文献   

4.
利用固相反应合成了稀土取代的复合氧化物Eu_(0.5)RE_(0.5)Fe_(0.5)Mn_(0.5)O_3(RE=La,Pr,Nd,Sm,Gd,Tb,Dy,Ho,Er,Tm,Yb).测量了这些化合物的XRD和XPS谱。在XPS研究中发现,稀土取代而使稀土元素本身的结合能相对于其倍半氧化物中的有所降低;在取代的复合氧化物中,随着RE离子半径的减小,Fe、Mn的结合能随之增加。  相似文献   

5.
利用固相反应合成了Eu0.5RE0.5Fe0.5Mn0.5O3(RE=La,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Y)等化合物。测量了其XRD谱及57FeMssbauer谱。实验发现,随着RE原子序数的增加,样品的晶胞体积减小,Fe在化合物中处于Fe3+的高自旋状态,57Fe的四极裂矩与样品的畸变参数D成线性关系。  相似文献   

6.
Structural Chemistry - The crystal structures of quaternary R3Fe0.5SnS7, R3Co0.5SnS7 and R3Ni0.5SnS7 (R = Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy and Ho) compounds of La3Mn0.5SiS7 structure type (space...  相似文献   

7.
利用固相反应合成了Eu_(0.5)RE_(0.5)Fe_(0.5)Mn_(0.5)O_3(RE=La,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Y)等化合物。测量了其XRD谱及~(57)FeMssbauer谱.实验发现,随着RE原子序数的增加,样品的晶胞体积减小,Fe在化合物中处于Fe~(3+)的高自旋状态,~(57)Fe的四极裂矩与样品的畸变参数D成线性关系。  相似文献   

8.
Fluoroplatinates(IV) of the Lanthanides LnF[PtF6] (Ln = Pr, Sm, Gd, Tb, Dy, Ho, Er) For the first time fluorides LnF[PtF6] (Ln = Pr, Sm, Gd, Tb, Dy, Ho, Er), all yellow have been obtained. From single crystal data they crystallize monoclinic, space group P21/n?C (No. 14), Z = 4, Pr: a = 1 125.77(19) pm, b = 559.04(7) pm, c = 910.27(17) pm, β = 107.29(1)°; Sm: a = 1 114.63(31) pm, b = 552.70(12) pm, c = 898.02(20) pm, β = 107.24(2)°; Gd: a = 1 112.12(15) pm, b = 551.22(7) pm, c = 891.99(11) pm, β = 107.09(1)°; Tb (Powder data): a = 1 108.88(20) pm, b = 552.71(9) pm, c = 889.56(16) pm, β = 107.30(1)°; Dy: a = 1 100.28(23) pm, b = 547.77(8) pm, c = 882.41(13) pm, β = 107.32(1); Ho: a = 1 099.11(16) pm, b = 546.16(7) pm, c = 879.45(15) pm, β = 107.34(1)°; Er: a = 1 095.10(16) pm, b = 544.82(10) pm, c = 874.85(14) pm, β = 107.37(1)°.  相似文献   

9.
Tkachuk AV  Mar A 《Inorganic chemistry》2005,44(7):2272-2281
The rare-earth intermetallic compounds (RE)12Co5Bi (RE = Y, Gd, Tb, Dy, Ho, Er, Tm) were prepared by arc-melting and annealing at 600 degrees C. These compounds extend the previously known (RE)6M2+xX1-x (M = Co, Ni; X = Ga, In, Sn, Pb) series with the Ho6Co2Ga-type structure to X = Bi. The crystal structure of Ho12Co5Bi was refined by the Rietveld method from powder X-ray diffraction data obtained using synchrotron radiation (Pearson symbol oI36, orthorhombic, space group Immm, Z = 2, a = 9.37598(14) A, b = 9.37871(14) A, c = 9.85465(13) A). Unlike other Ho6Co2Ga-type compounds, the 2a site in Ho12Co5Bi is exclusively occupied by Co atoms. Four-probe electrical resistivity measurements on sintered polycrystalline samples of (RE)12Co5Bi indicated metallic behavior. Magnetic measurements revealed behavior ranging from frequency-dependent maxima in the ac susceptibility for Y12Co5Bi to possible ferrimagnetic ordering for Gd12Co5Bi to antiferromagnetic ordering with metamagnetic transitions for the remaining compounds. As confirmed by band structure calculations using Y12Co5Bi as a model compound, Y-Y and Y-Co interactions are the most important bonding components, but matrix effects are likely responsible for anomalously short Co-Co contacts in the structure.  相似文献   

10.
使用复杂晶体化学键理论计算了La0.5R0.5Ba2Cu3O7(R=Pr,Nd,Sm,Eu,Gd,Dy,Y,Ho,Er,Tm,Yb,Lu)(La-R123),Pr0.5R0.5Ba2Cu3O7(R=La,Nd,Sm,Eu,Gd,Dy,Ho,Y,Er,Tm,Yb,Lu)(Pr-R123)以及RBa2Cu3O7(R=La,Pr,Nd,Sm,Eu,Gd,Dy,Ho,Y,Er,Tm)(R123)中Cu-O键的键共价性,结果表明Pr-R123,La-R123,以及R123都应具有超导性,而实验结果是La0.5Pr0.5Ba2Cu07,R0.5,Pr0.5Ba2Cu3O7(R=La,Nd,Sm,Eu,Gd)无超导性,产生这种矛盾的原因尚不明确,需要做进一步的研究。  相似文献   

11.
A new class of nonstoichiometric layered ternary rare-earth tin antimonides, RESn(x)()Sb(2) (RE = La, Ce, Pr, Nd, Sm), has been synthesized through reaction of the elements at 950 degrees C. In the lanthanum series LaSn(x)()Sb(2), tin can be incorporated from a maximum content of x approximately 0.7 or 0.8 to as low as x approximately 0.10. The structure of lanthanum tin diantimonide with the maximum tin content, LaSn(0.75)Sb(2), has been determined by single-crystal X-ray diffraction methods. It crystallizes in the orthorhombic space group -Cmcm with a = 4.2425(5) ?, b = 23.121(2) ?, c = 4.5053(6) ?, and Z = 4. The isostructural rare-earth analogues were characterized by powder X-ray diffraction. The structure of LaSn(0.75)Sb(2) comprises layers of composition "LaSb(2)" in which La atoms are coordinated by Sb atoms in a square-antiprismatic geometry. Between these layers reside chains of Sn atoms distributed over three crystallographically independent sites, each partially occupied at about 20%. The structure of LaSn(0.75)Sb(2) can be regarded as resulting from the excision of RE-Sb and Sb-Sb bonds in the related structures of binary rare-earth diantimonides, RESb(2), and then intercalation of Sn atoms between layers.  相似文献   

12.
合成了13种1,5-双(1′-苯基-3′-甲基-5′-吡唑啉酮-4′)-戊二酮-[1,5](BPMPPD)和溴化十六烷基吡啶盐(CPB)的稀土配合物.研究了配合物的红外光谱、紫外可见光谱、差热-热重谱、荧光光谱、核磁共振谱及摩尔电导等性质,发现配合物属离子型缔合物CP+[Ln(BPMPPD)2]-.Pr、Nd、Ho、Er、Tm配合物发生超灵敏跃迁.配合物的热分解温度具有"四分组"效应,Sm、Eu、Tb、Oy为线性荧光。  相似文献   

13.
邻氯苯甲酸稀土配合物的合成、表征及结构   总被引:3,自引:0,他引:3  
本文合成了邻氯苯甲酸与十五种稀土的配合物REL~3·H~2O(RE=Y,La~Lu,L=Clc~6H~4CO~2H),研究了它们的热分解及红外光谱.测定了钕、铽及镥三种稀土的配合物晶体结构,均属单斜晶系,空间群P2~1/n,稀土离子配位数为9,配合物呈无限链状聚合结构.  相似文献   

14.
Fourteen three-dimensional coordination polymers of general formula [Ln(lNO)(H2O)(SO4)]n, where Ln = La, 1.La; Ce, 2.Ce; Pr, 3.Pr; Nd, 4.Nd; Sm, 5.Sm; Eu, 6.Eu; Gd, 7.Gd; Tb, 8.Tb; Dy, 9.Dy; Ho, 10.Ho; Er. 11.Er; Tm, 12.Tm; Yb, 13.Yb; and Lu, 14.Lu; INO = isonicotinate-N-oxide, have been synthesized by hydrothermal reactions of Ln3+, MnCO3, MnSO4 x H2O, and isonicotinic acid N-oxide (HINO) at 155 degrees C and characterized by single-crystal X-ray diffraction, IR, thermal analysis, luminescence spectroscopy, and the magnetic measurement. The structures are formed by connection of layer, chain, or dimer of Ln-SO4 by the organic connector, INO. They belong to three structural types that are governed exclusively by the size of the ions: type I for the large ions, La, Ce, and Pr; type II for the medium ions, Nd, Sm, Eu, Gd, and Tb; and type III for the small ions, Dy, Ho, Er, Tm, Yb, and Lu. Type I consists of two-dimensional undulate Ln-sulfate layers pillared by INO to form a three-dimensional network. Type II has a 2-fold interpenetration of "3D herringbone" networks, in which the catenation is sustained by extensive pi-pi interactions and O-H...O and C-H...O hydrogen bonds. Type III comprises one-dimensional chains that are connected by INO bridges, resulting in an alpha-Po network. The progressive structural change is due to the metal coordination number decreasing from nine for the large ions via eight to seven for the small ions, demonstrating clearly the effect of lanthanide contraction. The sulfate ion acts as a micro4- or micro3-bridge, connecting two, three, or four metals, and is both mono- and bidentate. The INO ligand acts as a micro3- or micro2-bridge with carboxylate group in syn-syn bridging or bidentate chelating mode. The materials show considerably high thermal stability. The magnetic properties of 4.Nd, 6.Eu, 7.Gd, and 13.Yb and the luminescence properties of 6.Eu and 8.Tb are also investigated.  相似文献   

15.
本文利用非等温DSC曲线对十二种镧系元素异硫氰酸盐与苄胺形成的配合物Ln(NCS)3·4C6H5CH2NH2(Ln=La、Pr、Nd、Sm、Eu、Ge、Tb、Dy、Ho、Er、Tm、Yb)进行了非等温动力学研究, 并运用积分法和微分法进行了分析, 推断了它们的热分解反应机理函数。  相似文献   

16.
苯甲基苯甲酰基吡唑酮;1-苯基-3-甲基-4-苯甲酰基吡唑酮-5缩氨基硫脲稀土配合物的合成、表征及抑菌活性  相似文献   

17.
The compounds RE4FeGa(12-x)Ge(x) (RE = Sm, Tb) were discovered in reactions employing molten Ga as a solvent at 850 degrees C. However, the isostructural Y4FeGa(12-x)Ge(x) was prepared from a direct combination reaction. The crystal structure is cubic with space group Imm, Z = 2, and a = 8.657(4) A and 8.5620(9) A for the Sm and Tb analogues, respectively. Structure refinement based on full-matrix least squares on F(o)2 resulted in R1 = 1.47% and wR2 = 4.13% [I > 2(I)] for RE = Sm and R1 = 2.29% and wR2 = 7.12% [I > 2(I)] for RE = Tb. The compounds crystallize in the U4Re7Si6 structure type, where the RE atoms are located on 8c (1/4, 1/4, 1/4) sites and the Fe atoms on 2a (0, 0, 0) sites. The distribution of Ga and Ge in the structure, investigated with single-crystal neutron diffraction on the Tb analogue, revealed that these atoms are disordered over the 12d (1/4, 0, 1/2) and 12e (x, 0, 0) sites. The amount of Ga/Ge occupying the 12d and 12e sites refined to 89(4)/11 and 70(4)/30%, respectively. Transport property measurements indicate that these compounds are metallic conductors. Magnetic susceptibility measurements and M?ssbauer spectroscopy performed on the Tb analogue show a nonmagnetic state for Fe, while the Tb atoms carry a magnetic moment corresponding to a mu(eff) of 9.25 mu(B).  相似文献   

18.
本文报道了在水溶液中希土氧化物与3-(4-羟基-3-甲氧基苯基)丙烯酸形成配合物的合成方法。根据化学分析推断新化合物的组成为:RE(C_(10)H_9O_4)·xH_2O(RE表示希土元素,x=2或1)。通过溶解度、红外光谱和核磁共振谱等手段对所合成的化合物进行了结构与性质的研究。  相似文献   

19.
我们曾研究过BPMPHD对稀土元素的萃取规律,三元配合物,以及在有机溶剂中形成的某些二元配合物的性质。发现,由于BPMPHD是1种具有4个配位原子的螯型配合剂,它与稀土元素可以形成不同组成的配合物,对研究稀土新型配合物,探索金属间能量传递、光化学活性、催化性能均有重要意义,这类工作将会引起更多化学工作者的兴趣。  相似文献   

20.
Dynamic differential calorimetry has been employed to evaluate the heats of formation, heats and entropies of fusion of REPb3 compounds, where RE=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb. The results obtained have been estimated to be correct to within ±5–6‰ The general trend is a decrease in the heat of formation from La to Tm, which is correlated with the magnitude of the lanthanide contraction in these compounds.  相似文献   

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