Solid State Syntheses and Structure of LaPdCd2 and PrNi0.951(4)Cd2

2007 ◽  
Vol 62 (4) ◽  
pp. 610-612 ◽  
Author(s):  
Ahmet Doğan ◽  
Ute Ch. Rodewald ◽  
Rainer Pöttgen

The intermetallic cadmium compounds LaPdCd2 and PrNi0.951(4)Cd2 were synthesized from the elements in sealed tantalum tubes in an induction furnace. Both phases were investigated by X-ray diffraction on powders and single crystals: MgCuAl2-type, Cmcm, Z = 4, a = 431.9(1), b = 1015.7(4), c = 835.7(2) pm, wR2 = 0.0436, 326 F2 values, 16 variables for LaPdCd2 and a = 420.26(8), b = 981.0(2), c = 815.3(1) pm, wR2 = 0.0404, 604 F2 values, 17 variables for PrNi0.951(4)Cd2. A small nickel deficit was observed for the PrNi0.951(4)Cd2 crystal. The cadmium atoms build up orthorhombically distorted three-dimensional networks (Cd-Cd distances: 302 - 334 pm) that resemble the structure of hexagonal diamond, lonsdaleite. Together with the palladium (nickel) atoms, [PdCd2] and [Ni0.951(4)Cd2] networks are formed which leave distorted hexagonal channels for the rare earth atoms.

2017 ◽  
Vol 72 (11) ◽  
pp. 775-780
Author(s):  
Daniel Voßwinkel ◽  
Rainer Pöttgen

AbstractPolycrystalline RERh6Si4 (RE=La, Nd, Tb, Dy, Er, Yb) samples can be synthesized by arc-melting of the elements. Single crystals of LaRh6Si4, NdRh6Si4 and YbRh6Si4 were synthesized from the elements in bismuth fluxes (non-reactive flux medium). The structures were refined on the basis of single-crystal X-ray diffractometer data: LiCo6P4 type, P6̅m2, a=700.56(3), c=380.55(1) pm, wR2=0.0257, 317 F2 values, 19 variables for LaRh6Si4, a=698.4(5), c=377.7(2) pm, wR2=0.0578, 219 F2 values, 19 variables for NdRh6Si4 and a=696.00(3), c=371.97(1) pm, wR2=0.0440, 309 F2 values, 19 variables for YbRh6Si4. The rhodium and silicon atoms build up three-dimensional, covalently bonded [Rh6Si4]δ− polyanionic networks with Rh–Si distances ranging from 239 to 249 pm. The rare earth atoms fill larger cavities within channels of these networks and they are coordinated by six silicon and twelve rhodium atoms in the form of hexa-capped hexagonal prisms.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Michael Zoller ◽  
Hubert Huppertz

AbstractThe rare earth oxoborates REB5O8(OH)2 (RE = Ho, Er, Tm) were synthesized in a Walker-type multianvil apparatus at a pressure of 2.5 GPa and a temperature of 673 K. Single-crystal X-ray diffraction data provided the basis for the structure solution and refinement. The compounds crystallize in the monoclinic space group C2 (no. 5) and are composed of a layer-like structure containing dreier and sechser rings of corner sharing [BO4]5− tetrahedra. The rare earth metal cations are coordinated between two adjacent sechser rings. Further characterization was performed utilizing IR spectroscopy.


2011 ◽  
Vol 66 (7) ◽  
pp. 671-676 ◽  
Author(s):  
Trinath Mishra ◽  
Rainer Pöttgen

The equiatomic rare earth compounds REPtZn (RE = Y, Pr, Nd, Gd-Tm) were synthesized from the elements in sealed tantalum tubes by high-frequency melting at 1500 K followed by annealing at 1120 K and quenching. The samples were characterized by powder X-ray diffraction. The structures of four crystals were refined from single-crystal diffractometer data: TiNiSi type, Pnma, a = 707.1(1), b = 430.0(1), c = 812.4(1) pm, wR2 = 0.066, 602 F2, 21 variables for PrPt1.056Zn0.944; a = 695.2(1), b = 419.9(1), c = 804.8(1) pm, wR2 = 0.041, 522 F2, 21 variables for GdPt0.941Zn1.059; a = 688.2(1), b = 408.1(1), c = 812.5(1) pm, wR2 = 0.041, 497 F2, 22 variables for HoPt1.055Zn0.945; a = 686.9(1), b = 407.8(1), c = 810.4(1) pm, wR2 = 0.061, 779 F2, 20 variables for ErPtZn. The single-crystal data indicate small homogeneity ranges REPt1±xZn1±x. The platinum and zinc atoms build up three-dimensional [PtZn] networks (265 - 269 pm Pt-Zn in ErPtZn) in which the erbium atoms fill cages with coordination number 16 (6 Pt + 6 Zn + 4 Er). Bonding of the erbium atoms to the [PtZn] network proceeds via shorter RE-Pt distances, i. e. 288 - 293 pm in ErPtZn.


2013 ◽  
Vol 68 (5-6) ◽  
pp. 625-634 ◽  
Author(s):  
Bastian Reker ◽  
Samir F. Matar ◽  
Ute Ch. Rodewald ◽  
Rolf-Dieter Hoffmann ◽  
Rainer Pöttgen

Small single crystals of the Sm5Ge4-type (space group Pnma) germanides RE2Nb3Ge4 (RE = Sc, Y, Gd-Er, Lu) and Sc2Ta3Ge4 were synthesized by arc-melting of the respective elements. The samples were characterized by powder and single-crystal X-ray diffraction. In all structures, except for Sc2.04Nb2.96Ge4 and Sc2.19Ta2.81Ge4, the rare earth and niobium atoms show full ordering on the three crystallographically independent samarium sites of the Sm5Ge4 type. Two sites with coordination number 6 are occupied by niobium, while the slightly larger site with coordination number 7 is filled with the rare earth element. Small homogeneity ranges with RE=Nb and RE=Ta mixing can be expected for all compounds. The ordered substitution of two rare earth sites by niobium or tantalum has drastic effects on the coordination number and chemical bonding. This was studied for the pair Y5Ge4/Y2Nb3Ge4. Electronic structure calculations show larger charge transfer from yttrium to germanium for Y5Ge4, contrary to Y2Nb3Ge4 which shows stronger covalent bonding due to the presence of Nb replacing Y at two sites


1995 ◽  
Vol 50 (4) ◽  
pp. 577-580 ◽  
Author(s):  
H. Szillat ◽  
Hk. Müller-Buschbaum

Single crystals of (Cu0.22Mg0.78)BaNd2Mo4O16 have been prepared by crystallization from melts and investigated by X-ray methods. The compound crystallizes monoclinically, space group C62h - C12/c1, Z = 4, a = 5.351(1), b = 12.891(2), c = 19.391(4) Å,β = 90.899(14)° and is isotypic to CuKHo2Mo4O16. The crystal structure is dominated by BaO10 and NdO8 polyhedra forming a three-dimensional polyhedra network, which is filled by axially distorted (Cu,Mg)O6 octahedra and MoO4 tetrahedra.


2006 ◽  
Vol 61 (2) ◽  
pp. 159-163 ◽  
Author(s):  
Rainer Kraft ◽  
Sudhindra Rayaprol ◽  
C. Peter Sebastian ◽  
Rainer Pöttgen

AbstractThe new thallide EuPdTl2, synthesized from the elements in a sealed tantalum tube in a highfrequency furnace, was investigated by X-ray diffraction on powders and single crystals: MgCuAl2 type, Cmcm, Z = 4, a = 446.6(1), b = 1076.7(2), c = 812.0(2) pm, wR2 = 0.0632, 336 F2 values, 16 variables. The structure can be considered as an orthorhombically distorted, palladium-filled variant of the binary Zintl phase EuTl2. The palladium and thallium atoms build up a three-dimensional [PdTl2] polyanion with significant Pd-Tl (286 - 287 pm) and Tl-Tl (323 - 329 pm) interactions. The europium atoms fill distorted hexagonal channels of the [PdTl2] polyanion. Susceptibility measurements show a magnetic moment of 7.46(5) μB/Eu atom, indicative of divalent europium. EuPdTl2 is a soft ferromagnet with a Curie temperature of TC = 12.5(5) K.


2020 ◽  
Vol 76 (11) ◽  
pp. 1024-1033
Author(s):  
Fang-Hua Zhao ◽  
Shi-Yao Li ◽  
Wen-Yu Guo ◽  
Zi-Hao Zhao ◽  
Xiao-Wen Guo ◽  
...  

Two new CdII MOFs, namely, two-dimensional (2D) poly[[[μ2-1,4-bis(1H-benzimidazol-1-yl)butane](μ2-heptanedioato)cadmium(II)] tetrahydrate], {[Cd(C7H10O4)(C18H18N4)]·4H2O} n or {[Cd(Pim)(bbimb)]·4H2O} n (1), and 2D poly[diaqua[μ2-1,4-bis(1H-benzimidazol-1-yl)butane](μ4-decanedioato)(μ2-decanedioato)dicadmium(II)], [Cd2(C10H16O4)2(C18H18N4)(H2O)2] n or [Cd(Seb)(bbimb)0.5(H2O)] n (2), have been synthesized hydrothermally based on the 1,4-bis(1H-benzimidazol-1-yl)butane (bbimb) and pimelate (Pim2−, heptanedioate) or sebacate (Seb2−, decanedioate) ligands. Both MOFs were structurally characterized by single-crystal X-ray diffraction. In 1, the CdII centres are connected by bbimb and Pim2− ligands to generate a 2D sql layer structure with an octameric (H2O)8 water cluster. The 2D layers are further connected by O—H...O hydrogen bonds, resulting in a three-dimensional (3D) supramolecular structure. In 2, the CdII centres are coordinated by Seb2− ligands to form binuclear Cd2 units which are linked by bbimb and Seb2− ligands into a 2D hxl layer. The 2D layers are further connected by O—H...O hydrogen bonds, leading to an 8-connected 3D hex supramolecular network. IR and UV–Vis spectroscopy, thermogravimetric analysis and solid-state photoluminescence analysis were carried out on both MOFs. Luminescence sensing experiments reveal that both MOFs have good selective sensing towards Fe3+ in aqueous solution.


2008 ◽  
Vol 63 (9) ◽  
pp. 1127-1130 ◽  
Author(s):  
Falko M. Schappacher ◽  
Ute Ch. Rodewald ◽  
Rainer Pöttgen

New intermetallic compounds RE4TCd (RE = Y, La-Nd, Sm, Gd-Tm, Lu; T = Ni, Pd, Ir, Pt) were synthesized by melting of the elements in sealed tantalum tubes in a highfrequency furnace. They crystallize with the Gd4RhIn-type structure, space group F 4̄3m, Z = 16. The four gadolinium compounds were characterized by single crystal X-ray diffractometer data: a = 1361.7(1) pm, wR2 = 0.062, 456 F2 values, 19 variables for Gd4NiCd; a = 1382.1(2) pm, wR2 = 0.077, 451 F2 values, 19 variables for Gd4PdCd; a = 1363.6(2) pm, wR2 = 0.045, 494 F2 values, 19 variables for Gd4IrCd; a = 1379.0(1) pm, wR2 = 0.045, 448 F2 values, 19 variables for Gd4PtCd. The rare earth atoms build up transition metal-centered trigonal prisms which are condensed via common corners and edges, leading to three-dimensional adamantane-related networks. The cadmium atoms form Cd4 tetrahedra which fill voids left in the prisms’ network.


2016 ◽  
Vol 49 (6) ◽  
pp. 2053-2062 ◽  
Author(s):  
Harsh Yadav ◽  
Nidhi Sinha ◽  
Sahil Goel ◽  
Abid Hussain ◽  
Binay Kumar

Large single crystals of the promising molecular organic ferroelectric diisopropylammonium bromide (DIPAB) have been grown by the solution technique. A structural study was performed using single-crystal X-ray diffraction analysis. The twin element of a selected DIPAB crystal was identified by a morphological study. Intermolecular interactions present in the grown crystal were explored by Hirshfeld surface (three-dimensional) and fingerprint plot (two-dimensional) studies. In UV–vis spectroscopy, the DIPAB crystal has shown high transparency with a wide direct band gap of 5.65 eV. In the photoluminescence spectrum, sharp UV and blue emissions were observed at 370, 392, 417 and 432 nm. The electrical properties were investigated by measuring the dielectric constant (∊) and loss (tanδ) of the grown crystal. The DIPAB crystal exhibits a promising piezoelectric charge coefficient (d33) value of 18 pC N−1, which makes it suitable for transducer applications. A high ferroelectric Curie temperature (Tc≃ 425 K) with high remnant polarization (20.52 µC cm−2) and high coercive field (12.25 kV cm−1) were observed in the as-grown crystal. Vickers microhardness analysis shows that the value of Meyer's index (n= 7.27) belongs to the soft material range, which was also confirmed by void analysis along three crystallographic axes. It is shown that the DIPAB crystal has potential for optical, ferroelectric and piezoelectric applications.


2007 ◽  
Vol 62 (5) ◽  
pp. 642-646 ◽  
Author(s):  
Selcan Tuncel ◽  
Ute Ch. Rodewald ◽  
Bernard Chevalier ◽  
Rainer Pöttgen

Abstract The series of magnesium compounds RE4RhMg (RE = Y, La-Nd, Sm, Gd-Tm, Lu) was prepared by high-frequency melting of the elements in sealed tantalum tubes. All samples were investigated by powder X-ray diffraction. The structures with RE = Sm, Gd, Dy, Ho, and Er as rare earth metal components were refined from single crystal diffractometer data: Gd4RhIn-type, F4̄3m, Z = 16, a = 1392.1(1) pm, wR2 = 0.060, 616 F2 values, 19 variables for Sm4RhMg, a = 1380.8(2) pm, wR2 = 0.071, 530 F2 values, 19 variables for Gd4RhMg, a = 1366.9(1) pm, wR2 = 0.070, 594 F2 values, 20 variables for Dy4RhMg, a = 1355.7(2) pm, wR2 = 0.077, 578 F2 values, 20 variables for Ho3.52RhMg1.48, and a = 1355.4(2) pm, wR2 = 0.075, 559 F2 values, 20 variables for Er3.94RhMg1.06 .The rhodium atoms have slightly distorted trigonal prismatic rare earth coordination. Condensation of the RhRE6 prisms leads to a three-dimensional network which leaves large voids that are filled by regular Mg4 tetrahedra with a Mg-Mg distance of 312 pm in Sm4RhMg. The magnesium atoms have twelve nearest neighbors (3 Mg + 9 RE) in icosahedral coordination. In the structures with holmium and erbium, the RE1 positions which are not involved in the trigonal prismatic network exhibit RE1/Mg mixing. Shortest distances occur for Sm-Rh (286 pm) within the rigid three-dimensional network of condensed trigonal prisms.


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