On the Solid Solutions Eu1–xPt2Inx, Gd1–xPt2Inx, and Tm1–xNi2Inx

2005 ◽  
Vol 60 (4) ◽  
pp. 393-397 ◽  
Author(s):  
Mar’yana Lukachuk ◽  
Yaroslav M. Kalychak ◽  
Tom Nilges ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Coordination Number ◽  
Solid Solutions ◽  
Three Dimensional ◽  
Induction Melting ◽  
Single Crystal Diffraction ◽  
Laves Phases ◽  
X Ray ◽  
Arc Melting

The binary cubic Laves phases EuPt2, GdPt2, and TmNi2 form extended solid solutions Eu1−xPt2Inx, Gd1−xPt2Inx, and Tm1−xNi2Inx. Samples within these homogeneity ranges have been prepared from the elements by arc-melting on water-cooled copper chills or by induction melting in sealed tantalum tubes and subsequent annealing. The indides were characterized by X-ray powder and single crystal diffraction: MgCu2 type, Fd3̅m, a = 770.68(6) pm, wR2 = 0.0251, 67 F2 values, 6 variables for Eu0.94(3)Pt2In0.06(3), a = 769.16(6) pm, wR2 = 0.0244, 67 F2 values, 6 variables for Eu0.85(2)Pt2In0.15(2), a = 760.12(9) pm, wR2 = 0.0693, 65 F2 values, 6 variables for Gd0.79(5)Pt2In0.21(5), and MgCu4Sn type, F 4̅3m, a=700.27(6) pm, wR2=0.0368, BASF=0.13(2), 175 F2 values, 8 variables for TmNi4In. The platinum and nickel atoms build up three-dimensional networks of corner-sharing Pt4/2 and Ni4/2 tetrahedra. These networks leave larger voids of coordination number 16 that are filled with the rare earth (RE) and the indium atoms. While the thulium and indium atoms are ordered in TmNi4In, one observes mixed RE/In occupancies in Eu0.94(3)Pt2In0.06(3), Eu0.85(2)Pt2In0.15(2), and Gd0.79(5)Pt2In0.21(5)

The Ordered Laves Phases CeNi4Cd and RECu4Cd (RE = Ho, Er, Tm, Yb)

2005 ◽  
Vol 60 (5) ◽  
pp. 495-498 ◽  
Author(s):  
Ahmet Doğan ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Coordination Number ◽  
Induction Melting ◽  
Single Crystal Diffraction ◽  
Laves Phases ◽  
X Ray ◽  
The Rare Earth

The ternary ordered Laves phases CeNi4Cd and RECu4Cd (RE = Ho, Er, Tm, Yb) were synthesized by induction-melting of the elements in sealed tantalum tubes. The compounds were characterized by X-ray powder and single crystal diffraction: MgCu4Sn type, F 4̄3m, a = 706.9(2) pm for CeNi4Cd, a = 723.1(2) pm for HoCu4Cd, a = 717.7(3) pm for ErCu4Cd, a = 714.2(1) pm for TmCu4Cd, and a = 713.10(7) pm for YbCu4Cd. The nickel and copper atoms build up threedimensional networks of corner-sharing Ni4/2 and Cu4/2 tetrahedra. These networks leave voids of coordination number 16 that are filled with the rare earth (RE) and cadmium atoms.

scholarly journals Intermetallic REPtZn Compounds with TiNiSi-type Structure

2011 ◽  
Vol 66 (7) ◽  
pp. 671-676 ◽  
Author(s):  
Trinath Mishra ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Coordination Number ◽  
High Frequency ◽  
Three Dimensional ◽  
Type Structure ◽  
Rare Earth Compounds ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
X Ray

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.

Single-crystal Data of Ternary Germanides RE2Nb3Ge4 (RE = Sc, Y, Gd–Er, Lu) and Sc2Ta3Ge4 with Ordered Sm5Ge4-type Structure

2013 ◽  
Vol 68 (5-6) ◽  
pp. 625-634 ◽  
Author(s):  
Bastian Reker ◽  
Samir F. Matar ◽  
Ute Ch. Rodewald ◽  
Rolf-Dieter Hoffmann ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Coordination Number ◽  
Electronic Structure Calculations ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Arc Melting ◽  
Structure Calculations ◽  
The Rare Earth

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

Ternary Gallides REMgGa (RE = Y, La, Pr, Nd, Sm–Tm, Lu) – Synthesis and Crystal Chemistry

2003 ◽  
Vol 58 (9) ◽  
pp. 827-831 ◽  
Author(s):  
Rainer Kraft ◽  
Martin Valldor ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Cell Volume ◽  
Coordination Number ◽  
High Frequency ◽  
Three Dimensional ◽  
Gallium Atom ◽  
X Ray ◽  
Trigonal Prismatic Coordination ◽  
Trigonal Prismatic

The title compounds have been synthesized by reacting the elements in sealed niobium or tantalum tubes in a high-frequency furnace. They crystallize with the hexagonal ZrNiAl type structure, space group P62m. All gallides have been characterized through their X-ray powder diffractogram. The cell volume decreases from the lanthanum to the lutetium compound as expected from the lanthanoid contraction. The structures of LaMgGa, PrMgGa, NdMgGa, SmMgGa and TmMgGa have been refined from single crystal diffractometer data. The structures contain two crystallographically independent gallium sites which both have a trigonal prismatic coordination: Ga1 by six RE and Ga2 by six Mg atoms. These trigonal prisms are capped on the rectangular sites by three Mg (RE) atoms, leading to coordination number 9 for each gallium atom. Together, the gallium and magnesium atoms form a three-dimensional [MgGa] network in which the rare earth atoms fill distorted hexagonal channels. Within the network the magnesium atoms have short Mg-Mg contacts, i. e. 312 pm in SmMgGa. The Mg-Ga distances in that gallide range from 284 to 287 pm. Bonding in the network is thus governed by strong Mg-Ga and Mg-Mg bonding. EuMgGa crystallizes with the orthorhombic TiNiSi type: Pnma, a = 783.1(2), b = 472.8(1), c = 829.8(2) pm.

Rhodium-rich silicides RERh6Si4 (RE=La, Nd, Tb, Dy, Er, Yb)

2017 ◽  
Vol 72 (11) ◽  
pp. 775-780
Author(s):  
Daniel Voßwinkel ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Single Crystals ◽  
Three Dimensional ◽  
X Ray ◽  
Arc Melting ◽  
Covalently Bonded ◽  
Reactive Flux ◽  
The Rare Earth

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.

Cd4 Tetrahedra and Condensed RE6Rh Trigonal Prisms as Building Units in the Rare Earth-rich Compounds RE15Rh5Cd2 (RE = La, Ce, Pr, Nd)

2011 ◽  
Vol 66 (6) ◽  
pp. 559-564 ◽  
Author(s):  
Frank Tappe ◽  
Ute Ch. Rodewald ◽  
Rolf-Dieter Hoffmann ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Powder Diffraction ◽  
Three Dimensional ◽  
Induction Melting ◽  
X Ray ◽  
Dimensional Network ◽  
New Type ◽  
The Rare Earth ◽  
Trigonal Prisms

The rare earth-rich compounds RE15Rh5Cd2 (RE = La, Ce, Pr, Nd) were synthesized by induction melting of the elements in sealed tantalum tubes and characterized by X-ray powder diffraction. The structure of La15Rh5Cd2 was refined from single-crystal diffractometer data: new type, R3m, a = 1016.4(2), c = 4418.7(9) pm, wR2 = 0.0417, 2258 F2, 95 variables. Striking structural motifs in the RE15Rh5Cd2 intermetallics are rhodium-centered trigonal prisms RE6Rh which are condensed via common corners and edges to a complex three-dimensional network which leaves cavities for Cd4 tetrahedra and RE6 octahedra. The structural relationship with the recently discovered structure types Gd4RhIn and Pr23Ir7Mg4 is discussed.

On the Silicides EuIr2Si2 and Lu5Si3

2004 ◽  
Vol 59 (9) ◽  
pp. 969-974 ◽  
Author(s):  
Ute Ch. Rodewald ◽  
Birgit Heying ◽  
Dirk Johrendt ◽  
Rainer Pöttgen
Keyword(s):  
Single Crystal ◽  
Chemical Bonding ◽  
Induction Furnace ◽  
Three Dimensional ◽  
Single Crystal Diffraction ◽  
X Ray ◽  
Arc Melting ◽  
Sample Chamber ◽  
Trigonal Prismatic Coordination ◽  
Trigonal Prismatic

EuIr2Si2 was synthesized from the elements in a sealed tantalum tube in a water-cooled sample chamber of an induction furnace. Lu5Si3 was obtained by arc-melting of the elements. Both silicides were investigated by X-ray powder and single crystal diffraction: BaAl4 type, I4/mmm, a = 407.4(1), c = 1010.8(7) pm, wR2 = 0.0492, 134 F2 values, 9 variables for EuIr2Si2 and Mn5Si3 type, P63/mcm, a = 820.0(1), c = 614.2(1) pm, wR2 = 0.0511, 311 F2 values and 12 variables for Lu5Si3. The iridium and silicon atoms in EuIr2Si2 build up a three-dimensional [Ir2Si2] network with Ir-Si and Si-Si interactions. The europium atoms fill cages within the network. The metal-rich silicide Lu5Si3 contains columns of face-sharing, empty Lu6 octahedra and isolated silicon atoms in a distorted tri-capped trigonal prismatic coordination. Chemical bonding in these silicides is briefly discussed.

SrPdGa3 type gallides RERhGa3 with RE=La, Ce and Pr

2020 ◽  
Vol 235 (3) ◽  
pp. 53-57
Author(s):  
Stefan Seidel ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Diffraction Data ◽  
Three Dimensional ◽  
Subsequent Annealing ◽  
Crystal Chemical ◽  
X Ray Diffraction ◽  
Muffle Furnace ◽  
X Ray ◽  
Arc Melting

AbstractThe ternary rare earth gallides RERhGa3 with RE = La, Ce and Pr were synthesized by arc-melting and subsequent annealing in a muffle furnace. The gallides were characterized through Guinier powder patterns and the structure of LaRhGa3 was refined from single-crystal X-ray diffraction data: SrPdGa3 type, Cmcm, a = 639.2(2), b = 1030.9(2), c = 589.3(2) pm, wR2 = 0.0964, 416 F2 values and 19 variables. The rhodium and gallium atoms build up a three-dimensional polyanionic network [RhGa3] which is stabilized through Rh–Ga (245–251 pm) and Ga–Ga (267–295 pm) bonds and filled by the lanthanum atoms. The crystal chemical relationship with the structures of LaRh2Ge2 (ThCr2Si2 type), LaRh2Ga2 (CaBe2Ge2 type) and LaRhGe3 (BaNiSn3 type) is discussed.

Ternary Thallides REMgTl (Re = Y, La – Nd, Sm, Gd – Tm, Lu)

2005 ◽  
Vol 60 (3) ◽  
pp. 265-270 ◽  
Author(s):  
Rainer Kraft ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Rare Earth Metal ◽  
High Frequency ◽  
Three Dimensional ◽  
Earth Metal ◽  
X Ray ◽  
Sample Chamber ◽  
Trigonal Prismatic Coordination ◽  
Trigonal Prismatic

The rare earth metal (RE)-magnesium-thallides REMgTl (RE = Y, La-Nd, Sm, Gd-Tm, Lu) were prepared from the elements in sealed tantalum tubes in a water-cooled sample chamber of a high-frequency furnace. The thallides were characterized through their X-ray powder patterns. They crystallize with the hexagonal ZrNiAl type structure, space group P62m, with three formula units per cell. Four structures were refined from X-ray single crystal diffractometer data: α = 750.5(1), c = 459.85(8) pm, wR2 = 0.0491, 364 F2 values, 14 variables for YMgTl; α = 781.3(1), c = 477.84(8) pm, wR2 = 0.0640, BASF = 0.09(2), 425 F2 values, 15 variables for LaMgTl; α = 774.1(1), c = 473.75(7) pm, wR2 = 0.0405, 295 F2 values, 14 variables for CeMgTl; a = 760.3(1), c = 465.93(8) pm, wR2 = 0.0262, 287 F2 values, 14 variables for SmMgTl. The PrMgTl, NdMgTl, GdMgTl, TbMgTl, and DyMgTl structures have been analyzed using the Rietveld technique. The REMgTl structures contain two cystallographically independent thallium sites, both with tri-capped trigonal prismatic coordination: Tl1Mg3RE6 and Tl2Mg6RE3. Together the magnesium and thallium atoms form three-dimensional [MgTl] networks with Mg-Mg distances of 327 and Mg-Tl distances in the range 299 - 303 pm (data for CeMgTl)

Structure Refinement of CePtSi and Hydrogenation Behavior of CePdGe, CePtSi and CePtGe

2007 ◽  
Vol 62 (4) ◽  
pp. 613-616 ◽  
Author(s):  
Wilfried Hermes ◽  
Ute Ch. Rodewald ◽  
Bernard Chevalier ◽  
Rainer Pötgena
Keyword(s):  
Single Crystal ◽  
Diffraction Data ◽  
Structure Refinement ◽  
Three Dimensional ◽  
Subsequent Annealing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydride Formation ◽  
Arc Melting ◽  
Cerium Compounds

The intermetallic cerium compounds CePdGe, CePtSi, and CePtGe were synthesized from the elements by arc-melting and subsequent annealing. The structure of CePtSi was refined from single crystal X-ray diffraction data: LaPtSi-type (ordered α-ThSi2 version), 141md, a = 419.6(1) and c = 1450.0(5) pm, wR2 = 0.0490, 362 F2 values and 16 variables. The Pt-Si distances within the three-dimensional [PtSi] network are 242 pm, indicating strong Pt-Si interactions. Hydrogenation of the three compounds at 623 K and 4 MPa H2 gave no indication for hydride formation.

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