Role of crystal structure on the thermal expansion of Ln2W3O12 (Ln = La, Nd, Dy, Y, Er and Yb)

The negative thermal expansion material Y₂W₃O₁₂ belongs to Ln₂W₃O₁₂ family of compositions. The thermal expansion behavior of Ln₂W₃O₁₂ (Ln = La, Nd, Dy, Y, Er and Yb) members synthesized by the solid-state reaction have been studied and correlated to their crystal structure. The lighter rare earth tungstates (Ln = La, Nd and Dy) crystallize in monoclinic structure (C2/c) whereas the heavy rare earth tungstates (Ln = Y, Er and Yb) form the trihydrate orthorhombic Ln₂W₃O₁₂3H₂O at room temperature and above 400 K transforms to unhydrated orthorhombic structure (Pnca). The hot pressed (1273 K and 25 MPa) ceramic pellets have been studied for thermal expansion property by dilatometry and high temperature X-ray diffraction. The heavy rare earth tungstates show a large initial expansion up to 400 K, followed by a thermal contraction. The light rare earth tungstates, on the other hand, show thermal expansion. The difference in the thermal expansion behavior in Ln₂W₃O₁₂ series is attributed to the difference in the structural features. The heavy rare earth tungstates have corner sharing of LnO₆ octahedra with WO₄ tetrahedra, where the now well established mechanism of transverse vibrations operate. The light rare earth tungstates have edge sharing of LnO₈ polyhedra where in such a mechanism is absent.     

Studies of the defect structure for V3+ ions in wurtzite structure ZnO

By using crystal field theory, the optical spectra, zero field splitting and g factors have been calculated. The defect structure for V(3+) in ZnO crystal has been studied by using crystal field theory and first-principle calculations. The results show that, the V(3+) ions do not occupy the exact Zn(2+) site, but displaced along C(3) axis.     

Li2O-CaO-Gd2O3-SiO2:Eu,Bi体系的结构和发光性能之间的关系

用X射线粉末衍射法研究了Li₂O-CaO-Gd₂O₃-SiO₂:Eu,Bi发光体系的物相组成随Gd₂O₃含量的变化,探讨了不同硅酸盐物种和结构对Eu³⁺和Bi³⁺发光特性的影响。结果表明,无Gd₂O₃组分时发光体是β-CaSiO₄多晶体,当Gd₂O₃/SiO₂比超过2.5%时,Ca₂Gd₈(SiO₄)₆O₂和LiGd₉(SiO₄)₆O₂物相逐渐增加,当其成为主要物相时,EU³⁺发光呈数倍增强,这2种含钆物相的结构既利于EU³⁺的红光发射又利于敏化剂向激活剂传输能量,所形成的固熔体是优良的发光基质材料。     

Rare earth-copper-magnesium compounds RECu9Mg2 (RE=Y, La-Nd, Sm-Ho, Yb) with ordered CeNi3-type structure

A series of ternary compounds RECu₉Mg₂ (RE=Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Yb) have been synthesized via induction melting of elemental metal ingots followed by annealing at 400 °C for 4 weeks. Scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDXS) was used for examining microstructure and phase composition. These phases crystallize with an ordered version of the binary hexagonal structure type first reported for CeNi₃. The crystal structure was solved for TbCu₉Mg₂ from single crystal X-ray counter data (TbCu₉Mg₂-structure type, P6₃/mmc-space group, hP24-Pearson symbol, a=0.49886 (7) nm, c=1.61646 (3) nm, R_F=0.0474 for 190 unique reflections). The Rietveld refinement of the X-ray powder diffraction patterns of RECu₉Mg₂ confirmed the same crystal structure for the reported rare earth metals. The unit cell volumes for RECu₉Mg₂ smoothly follow the lanthanide contraction. The existence of a RECu₉Mg₂ phase was excluded for RE=Er and Tm under the investigated experimental conditions.     

Preparation and Crystal Structure of the Ternary Lanthanoid Nickel Arsenides Ln13Ni25As19 (Ln = Tm,Yb, and Lu)

The title compounds were prepared by reaction of the elemental components at high temperatures. They crystallize with a new structure type which was determined from single‐crystal X‐ray data of Tm₁₃Ni₂₅As₁₉: P 6, a = 1621.9(4) pm, c = 387.78(8) pm, Z = 1, R = 0.025 for 3164 structure factors and 119 variable parameters. The refinement of the occupancy parameters suggested a mixed Tm/Ni occupancy for one metal position and defects for one nickel site resulting in the composition Tm_12.57(1)Ni_25.22(2)As₁₉. These arsenides belong to a large structural family with a metal to metalloid ratio of 2 : 1.     

Single Crystals of C–La2Se3, C–Pr2Se3, and C–Gd2Se3 with Cation‐Deficient Th3P4‐Type Structure

Ruby‐red, bead‐shaped single crystals of C‐type La₂Se₃ (a = 905.21(6) pm), Pr₂Se₃ (a = 891.17(6) pm), and Gd₂Se₃ (a = 872.56(5) pm) are obtained by oxidation of the respective rare‐earth metal (M = La, Pr and Gd) with selenium (molar ratio 2 : 3) in evacuated silica tubes at 750 °C in the presence of fluxing CsCl within seven days. Their crystal structure belongs to a cation‐deficient Th₃P₄‐type variant (cubic, I 4 3d) according to M_2.667□_0.333Se₄ (Z = 4) or M₂Se₃ (Z = 5.333) offering coordination numbers of eight (Se^2– arranged as trigonal dodecahedra) to the M³⁺ cations. In spite of the high Cs⁺ activity in molten CsCl, no cesium incorporation into the M_5.333□_0.667Se₈‐frame structure (e. g. as CsM₅Se₈ with Z = 2) could be achieved, judged from both results of electron beam X‐ray microanalyses and refined occupation factors of the metal position very close to x = 8/9 for M_3xSe₄.     

Rare earth-rich cadmium compounds RE 4 TCd (T = Co, Ru, and Rh) with Gd4RhIn type structure

The rare earth-rich cadmium compounds RE ₄ TCd (RE = Y, La–Nd, Sm, and Gd–Tm, Lu; T = Co, Ru, and Rh) were prepared from the elements in sealed tantalum ampoules in an induction furnace. All samples were characterized by X-ray powder diffraction. The structures of Y₄RuCd (a = 1362.5(1) pm), La₄RuCd (a = 1415.9(1) pm), Gd₄RuCd (a = 1368.8(2) pm), La₄CoCd (a = 1417.9(4) pm), Gd₄CoCd (a = 1356.1(1) pm), and Gd₄RhCd (a = 1368.7(1) pm) were refined from single crystal X-ray diffractometer data. The RE ₄ TCd compounds crystallize with the cubic Gd₄RhIn type structure, space group F ${\bar 4}The rare earth-rich cadmium compounds RE ₄ TCd (RE = Y, La–Nd, Sm, and Gd–Tm, Lu; T = Co, Ru, and Rh) were prepared from the elements in sealed tantalum ampoules in an induction furnace. All samples were characterized by X-ray powder diffraction. The structures of Y₄RuCd (a = 1362.5(1) pm), La₄RuCd (a = 1415.9(1) pm), Gd₄RuCd (a = 1368.8(2) pm), La₄CoCd (a = 1417.9(4) pm), Gd₄CoCd (a = 1356.1(1) pm), and Gd₄RhCd (a = 1368.7(1) pm) were refined from single crystal X-ray diffractometer data. The RE ₄ TCd compounds crystallize with the cubic Gd₄RhIn type structure, space group F 3m. The transition metal atoms have tricapped trigonal prismatic rare earth coordination. The trigonal prisms are condensed via common edges, forming a rigid three-dimensional network with adamantane symmetry. Voids in these networks are filled by Cd₄ tetrahedra (304 pm Cd–Cd in Gd₄CoCd) and polyhedra of the RE1 atoms. The crystal chemical peculiarities are briefly discussed. Correspondence: Rainer P?ttgen, Institut für Anorganische und Analytische Chemie, Westf?lische Wilhelms-Universit?t Münster, Correnstrasse 30, 48149 Münster, Germany.     

Quaternary indides LaTIn3Mg (T = Rh and Ir) and CeIrIn3Mg with LaCoAl4 type structure

The quaternary indides LaTIn₃Mg (T = Rh and Ir) and CeIrIn₃Mg were prepared from the elements in sealed tantalum ampoules in an induction furnace. The samples were characterized by X-ray powder and single crystal data: LaCoAl₄ type, Pmma, Z = 2, a = 830.5(1), b = 436.1(1), c = 745.1(1) pm, wR2 = 0.038, 467 F ² values for LaRhIn_3.075Mg_0.925, a = 832.9(1), b = 436.5(1), c = 746.9(1) pm, wR2 = 0.077, 471 F ² values for LaIrIn_3.091Mg_0.909, and a = 832.2(1), b = 434.1(1), c = 743.9(1) pm, wR2 = 0.066, 465 F ² values for CeIrIn_3.07Mg_0.93 with 25 variables for each refinement. The transition metal, indium, and magnesium atoms build up three-dimensional [TIn₃Mg] networks which leave pentagonal prismatic voids for the lanthanum and cerium atoms. The transition metal atoms have tricapped trigonal prismatic coordination and the magnesium atoms fill distorted square prisms. All three crystals revealed a small degree of Mg/In mixing on the latter site.     

Yb2+3—xPd12—3+xP7 (x = 0.40): Different Ytterbium Species in a Substituted Structural Motif of the Zr2Fe12P7 Type

The new compound Yb_2+3—xPd_12—3+xP₇ x = 0.40(4)) was synthesized by sintering of a mixture of elemental components at 1100 °C with subsequent annealing at 800 °C. The crystal structure of Yb_2+3—xPd_12—3+xP₇ was solved and refined from X‐ray single‐crystal diffraction data: space group P6¯, a = 10.0094(4)Å, c = 3.9543(2)Å, Z = 1; R(F) = 0.022 for 814 observed unique reflections and 38 refined parameters. The atomic arrangement reproduces a structure motif of the hexagonal Zr₂Fe₁₂P₇ type in which one of the transition metal positions is substituted predominantly by ytterbium (Yb : Pd = 0.86(1) : 0.14). The ytterbium atoms are embedded in the 3D polyanion formed by palladium and phosphorus atoms. Two different environments for ytterbium atoms are present in the structure. Magnetic susceptibility measurements and XAS spectroscopy at the Yb L_III edge show the presence of ytterbium in two electronic configurations, 4?¹³ and 4?¹⁴. The following model was derived. Ytterbium atoms in the 3k site are in the 4?¹³ state, the two remaining positions contain ytterbium in intermediate‐valence states, giving totally 79 % ytterbium in the 4?¹³ electronic configuration.     

Syntheses,Crystal Structures,and Optical and Magnetic Properties of Some CsLnCoQ3 Compounds (Ln = Tm and Yb,Q = S; Ln = Ho and Yb,Q = Se)

The four new compounds CsTmCoS₃, CsYbCoS₃, CsHoCoSe₃, and CsYbCoSe₃ have been synthesized at 1123 K. These black‐colored isostructural compounds crystallize in the KZrCuS₃ structure type with four formula units in space group Cmcm of the orthorhombic system. The structure of these compounds is composed of layers separated by Cs atoms. Because there are no Q–Q bonds, the formal oxidation states of Cs/Ln/Co/Q are 1+/3+/2+/2?, respectively. CsHoCoSe₃ shows paramagnetic behavior with μ_eff = 11.9(1) μ_B, whereas CsYbCoS₃ displays an antiferromagnetic‐like transition at ～2.7 K with μ_eff = 5.85(1) μ_B. Both CsYbCoS₃ and CsYbCoSe₃ exhibit optical band gaps in the near infrared region and broad absorption bands at lower energies.     

Neue Thiophosphate: Die Verbindungen Li6Ln3(PS4)5 (Ln: Y,Gd, Dy,Yb, Lu) und Ag3Y(PS4)2

New Thiophosphates: The Compounds Li₆Ln₃(PS₄)₅ (Ln: Y, Gd, Dy, Yb, Lu) and Ag₃Y(PS₄)₂ The new thiophosphates Li₆Ln₃(PS₄)₅ (Ln: Y, Gd, Dy, Yb, Lu) were synthesized by heating mixtures of Ln, P, S, and Li₂S₄ at 900 °C (100 h) and they were investigated by single crystal X‐ray methods. The compounds with Ln = Y (a = 28.390(2), b = 10.068(1), c = 33.715(2) Å, β = 113.85(1)°), Gd (a = 28.327(2), b = 10.074(1), c = 33.822(2) Å, β = 114.297(7)°), Dy (a = 28.124(6), b = 10.003(2), c = 33.486(7) Å, β = 113.89(3)°), Yb (a = 28.178(3), b = 9.977(1), c = 33.392(4) Å, β = 113.65(1)°), and Lu (a = 28.169(6), b = 10.002(2), c = 33.432(7) Å, β = 113.54(3)°) are isotypic and crystallize in a new structure type (C2/c; Z = 12). Main feature are PS₄ tetrahedra isolated from each other surrounding the Ln and Li atoms via their S atoms. The coordination number of the five crystallographically independent Ln atoms is eight, but the polyhedra are quite different and they are interlinked to larger units extending in [010]. The environment of the Li atoms is irregular and formed by five to six S atoms. The crystal structure is compared with that of Li₉Ln₂(PS₄)₅ (Ln: Nd, Gd). For the synthesis of Ag₃Y(PS₄)₂ (a = 16.874(3), b = 9.190(2), c = 9.312(2) Å, β = 123.17(3)°) a mixture of Y, P, S, and Ag₂S was heated to 700 °C (50 h). The thiophosphate crystallizes in a new structure type (C2/c; Z = 4) composed of isolated PS₄ tetrahedra. The two crystallographically independent Ag atoms are surrounded by four S atoms in the shape of distorted tetrahedra. The Ag(1)S₄ polyhedra are cornershared to strands running along [001], which are linked together via Ag(2)S₄ tetrahedra. The environment of the Y atoms is composed of eight S atoms each building distorted square antiprisms. These polyhedra are connected with each other via common edges to a strand running along [001].     

Synthesis and crystal structure of the isotypic rare earth thioborates Ce[BS3], Pr[BS3], and Nd[BS3]

The orthothioborates Ce[BS₃], Pr[BS₃] and Nd[BS₃] were prepared from mixtures of the rare earth (RE) metals together with amorphous boron and sulfur summing up to the compositions CeB₃S₆, PrB₅S₉ and NdB₃S₆. The following preparation routes were used: solid state reactions with maximum temperatures of 1323 K and high-pressure high-temperature syntheses at 1173 K and 3 GPa. Pr[BS₃] and Nd[BS₃] were also obtained from rare earth chlorides RECl₃ and sodium thioborate Na₂B₂S₅ by metathesis type reactions at maximum temperatures of 1073 K. The crystal structure of the title compounds was determined from X-ray powder diffraction data. The thioborates are isotypic and crystallize in the orthorhombic spacegroup Pna2₁ (No. 33; Z=4; Ce: , , ; Pr: , , ; Nd: , , ) . The crystal structures contain isolated [BS₃]^3‐ groups with boron in trigonal-planar coordination. The sulfur atoms form the vertices of undulated kagome nets, which are stacked along [100] according to the sequence ABAB. Within these nets every second triangle is occupied by boron and the large hexagons are centered by rare earth ions, which are surrounded by overall nine sulfur species.     

Sol-Gel Synthesis of Nano-Scaled BaTiO3, BaZrO3 and BaTi0.5Zr0.5O3 Oxides via Single-Source Alkoxide Precursors and Semi-Alkoxide Routes

Sol-gel synthesis of nano-sized BaTiO₃, BaZrO₃ and BaTi_0.5Zr_0.5O₃ ceramics using alkoxide and semi-alkoxide routes has been investigated and the pervoskites obtained have been compared with respect to crystallisation temperature, crystallite size and compositional purity. Heterometal alkoxides containing two (for BaTiO₃ and BaZrO₃) and three (for BaTi_0.5Zr_0.5O₃) different metals were used as single-source precursors in the alkoxide route while semi-alkoxide synthesis was performed by reacting barium hydroxide or acetate with Ti and/or Zr alkoxides. Semi-alkoxide synthesis also produces stoichiometric and phase-pure oxides, however, at temperatures higher than 1000°C. At temperatures below 1000°C, BaCO₃ and small amounts of other undesired phases (e.g., BaTi₂O₄) were present in the oxides derived from semi-alkoxide synthesis. Thermal behaviour, studied by TGA/DTA measurements, shows that thermal decomposition occurs in three major steps and depends on the educt composition and the synthesis route. Among alkoxide derived powders, crystalline BaTi_0.5Zr_0.5O₃ phase is formed at 400°C while complete crystallisation of BaMO₃ ceramics occurs around 600°C. The cubic to tetragonal phase transition for BaTiO₃ is clearly observed at relatively low-temperature of 800°C. The stoichiometry and phase homogeneity of the obtained powders were demonstrated by energy dispersive X-ray analysis and powder diffractometry. The averaged crystallite size of the obtained nano-ceramics was evaluated using the FormFit programme. SEM and TEM observations revealed a high microstructural uniformity.     

Effect of arrangement of nano and micro barium titanate (BaTiO3) particles on the enhanced dielectric constant of high‐density polyethylene (HDPE)/BaTiO3

The aim of this study is to improve the dielectric and mechanical properties of HDPE/BaTiO₃ composites by binary BaTiO₃ particles, when the volume fraction of BaTiO₃ is constant. In this study, it was found that the pack density of binary BaTiO₃ particles in HDPE/BaTiO₃ composite relies on particle ratio and volume fraction of small particles. It is found that the addition of 50 vol % 1600 nm BaTiO₃ particles can boost the dielectric constant of HDPE control from 2 to 30 (14 times higher) at 40 Hz and 19 (8.5 times higher) at 40 MHz, respectively. When the particle ratio was 4, the substitution of 10 vol % 1600 nm BaTiO₃ particles by 10 vol % 400 nm BaTiO₃ particles can further enhance the dielectric constant of HDPE/L‐BT (10/10) from 30 to 50 (67% increase) at 40 Hz and from 19 to 42 (121% increase) at 40 MHz, respectively, without greatly influencing the volume resistivity of HDPE composites. In addition, the thermal conductivity of HDPE with binary BaTiO₃ particles were all above 2.0 W/(m•K). © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 1101–1108     

Preparation, crystal structure and electrorheological performance of nano-sized particle materials containing ZrO2

A series of nano-sized particle materials containing ZrO₂ was prepared and their compositions were determined by elemental analysis and thermogravimetric analysis (TGA). The effect of particle size and crystal structure type (lattice and space group) on the ER performance of these materials was investigated by X-ray diffraction (XRD) analysis, Raman spectra, the particle size analysis and rheological measurement. Their electrorheological (ER) effects show that the ER activities of the ZrO₂ materials doped with rare earth (RE=Y, La, Ce, Gd, Tb), whose grain sizes were less than that of pure ZrO₂, were lower than that of pure ZrO₂, which belongs to the tetragonal crystal system. The ER activity of Y₂O₃-ZrO₂ is the strongest among all the RE-doped ZrO₂ materials. The ER activity of the tetragonal phase ZrO₂ is higher than that of the monoclinic phase ZrO₂.     

Ternary rare earth metal boride carbides containing two-dimensional boron–carbon network: The crystal and electronic structure of R2B4C (R=Tb, Dy, Ho, Er)

The ternary rare earth boride carbides R₂B₄C (R=Tb, Dy, Ho, Er) have been synthesized by reacting the elements at temperatures between 1800 and 2000K. The crystal structure of Dy₂B₄C has been determined from single-crystal X-ray diffraction data. It crystallizes in a new structure type in the orthorhombic space group Immm (a=3.2772(6) Å, b=6.567(2) Å, c=7.542(1) Å, Z=2, R1=0.035 (wR₂=0.10) for 224 reflections with I_o>2σ(I_o)). Boron atoms form infinite chains of fused B₆ rings in [100] joined with carbon atoms into planar, two-dimensional networks which alternate with planar sheets of rare earth metal atoms. The electronic structure of Dy₂B₄C was also analyzed using the tight-binding extended Hückel method.     

La[B5O8(OH)(H2O)]NO3•2H2O的合成与结构

采用熔融硼酸法合成了一种具有层状结构的新型水合稀土多硼酸盐, La[B₅O₈(OH)(H₂O)]NO₃•2H₂O, 并利用单晶X射线衍射技术确定了它的结构. 它属于单斜晶系, P21/n空间群. 其基本构建单元 (fundamental building block, 简称FBB)是由三个BO4和两个BO3基团所构成的一个双三元环[B5O12]基团. 结构中每一个FBB通过共顶点氧原子与周围四个同样的单元连接成具有九元环窗口的二维[B5O10]层, La³⁺位于九元环中心附近. [B5O10]层沿着b方向进行堆积, 硝酸根离子和结构中部分结晶水分子位于相邻的[B5O10]层之间.     

Synthesis,Structure, and Magnetic Properties of the Silicides <Emphasis Type="BoldItalic">RE</Emphasis>IrSi (<Emphasis Type="Italic">RE</Emphasis> = Ce,Pr, Er,Tm, Lu) and SmIr<Subscript>0.266(8)</Subscript>Si<Subscript>1.734(8)</Subscript>

Summary. The equiatomic rare earth metal–iridium–silicides REIrSi (RE=Ce, Pr, Er, Tm, Lu) were prepared by arc-melting of the elements and subsequent annealing. All silicides were characterized through their X-ray powder patterns. The structures of CeIrSi, ErIrSi, and LuIrSi were refined from X-ray single crystal diffractometer data: LaIrSi type, P2₁3, a=629.15(2)pm, wR2=0.1232, 280F² values, and 11 variable parameters for CeIrSi; TiNiSi type, Pnma, a=673.4(1), b=416.07(5), c=744.88(9)pm, wR2=0.0705, 339F² values, and 20 variable parameters for ErIrSi, and a=664.0(3), b=412.9(1), c=742.6(1)pm, wR2=0.0398, 496F² values, and 20 variable parameters for LuIrSi. The iridium and silicon atoms in CeIrSi, ErIrSi, and LuIrSi build three-dimensional [IrSi] networks where the iridium atoms have three (CeIrSi, Ir–Si 229pm) and four (ErIrSi, Ir–Si 247–258pm; LuIrSi, Ir–Si 245–256pm) silicon neighbors. The [IrSi] networks leave larger channels in which the cerium, erbium, and lutetium atoms are located. Temperature dependent susceptibility data for LuIrSi indicate Pauli paramagnetism. CeIrSi shows Curie-Weiss paramagnetism above 100K with an experimental magnetic moment of 2.56(2)_B/Ce atom. With samarium as rare earth metal component the silicide SmIr_0.266(8)Si_1.734(8) with -ThSi₂ type structure was obtained: I4₁/amd, a=409.3(1), c=1397.2(5)pm, wR2=0.0575, 161F² values, and 9 variable parameters. Within the three-dimensional [Ir_0.266Si_1.734] network the Ir/Si–Ir/Si distances range from 230 to 237pm.     

Preparation and Crystal Structure of Rare Earth Rhenates: the Series Ln5Re2O12 with Ln = Y,Gd–Lu,and the Praseodymium Rhenates Pr3ReO8, Pr3Re2O10, and Pr4Re2O11

The crystal structure of the known compounds Ln₅Re₂O₁₂ (Ln = Y, Gd, Dy–Lu) and the new isotypic terbium rhenate Tb₅Re₂O₁₂ was determined from X‐ray data of a twinned crystal of Ho₅Re₂O₁₂: B2/m, a = 1236.5(4) pm, b = 748.2(2) pm, c = 563.8(1) pm, γ = 107.73(3)°, Z = 2, R = 0.034 for 379 structure factors and 37 variable parameters. The rhenium atoms (oxidation number +4.5) have octahedral oxygen coordination. These ReO₆ octahedra share edges, thus forming infinite strings with alternating short and long Re–Re distances: 243.6(2) and 320.1(2) pm. Of the three holmium positions two are surrounded by seven oxygen atoms and the third one has octahedral oxygen coordination. The crystal structure of Pr₃ReO₈ was refined from single‐crystal X‐ray data: P2₁/a, a = 1498.0(2) pm, b = 749.09(8) pm, c = 610.48(9) pm, γ = 110.39(1)°, R = 0.017 for 2082 F values and 110 variable parameters. It is isotypic with a structure first determined for Sm₃ReO₈. The new compounds Pr₃Re₂O₁₀ and Pr₄Re₂O₁₁ were prepared by reaction of elemental praseodymium with the metaperrhenate Pr(ReO₄)₃. They were characterized through their X‐ray powder diagrams. Pr₃Re₂O₁₀ was found to be monoclinic: a = 778.47(9) pm, b = 773.62(9) pm, c = 706.10(8) pm, β = 114.77(1)°. It is isotypic with La₃Os₂O₁₀ and La₃Re₂O₁₀. Pr₄Re₂O₁₁ crystallizes with Nd₄Re₂O₁₁ type structure with the tetragonal lattice constants a = 1272.49(3) pm, c = 562.29(2) pm. The compounds Nd₄Re₂O₁₁ and Sm₄Re₂O₁₁ are confirmed. The magnetic properties of Ho₅Re₂O₁₂, Tb₅Re₂O₁₂, Pr₃Re₂O₁₀, Pr₄Re₂O₁₁, Nd₄Re₂O₁₁, and Sm₄Re₂O₁₁ were investigated with a Faraday balance. None of these compounds shows magnetic order above 200 K.     

Crystal Structure of the RE2PbS4 (RE = Y,Dy, Ho,Er, and Tm) Compounds and a Comparison with the Crystal Structures of other Rare Earth Lead Chalcogenides

The crystal structure of the RE₂PbS₄ (RE = Y, Dy, Ho, Er and Tm) compounds (space group Cmc2₁, Pearson symbol oC112, a = 0.79301(3) nm, b = 2.86966(9) nm, c = 1.20511(5) nm, R_Bragg = 0.0979 for Y₂PbS₄; a = 0.79484(8) nm, b = 2.8721(3) nm, c = 1.2039(1) nm, for Dy₂PbS₄; a = 0.79081(2) nm, b = 2.86222(7) nm, c = 1.20220(4) nm, R_Bragg = 0.0859 for Ho₂PbS₄; a = 0.7863(2) nm, b = 2.8525(5) nm, c = 1.1995(2) nm, R1 = 0.0482 for Er₂PbS₄ and a = 0.78419(3) nm, b = 2.84184(9) nm, c = 1.19655(4) nm, R_Bragg = 0.0893 for Tm₂PbS₄) was investigated by means of X‐ray single crystal and powder diffraction. Each RE atoms is octahedrally coordinated by six S atoms. Each Pb atoms is surrounded by seven S atoms to form a mono‐capped trigonal prism.