Transition Metal-centered Trigonal Prisms as BuildingUnits in RE14T3In3 (RE = Y, Ho, Er, Tm, Lu; T = Pd, Ir, Pt) and Y4IrIn

2007 ◽  
Vol 62 (12) ◽  
pp. 1574-1580 ◽  
Author(s):  
Roman Zaremba ◽  
Ute Ch. Rodewald ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Transition Metal ◽  
Three Dimensional ◽  
Crystal Chemical ◽  
Crystal Data ◽  
Space Group ◽  
X Ray ◽  
Type Space ◽  
Arc Melting ◽  
Trigonal Prisms

The indides RE14T3In3 (RE = Y, Ho, Er, Tm, Lu; T = Pd, Ir, Pt) and Y4IrIn were synthesized from the elements by arc-melting and subsequent annealing for crystal growth. Their structures were characterized on the basis of X-ray powder and single crystal data: Lu14Co3In3-type, space group P42/nmc, a = 970.2(1), c = 2340.7(5) pm for Y13.95Pd3In3.05, a = 959.7(1), c = 2309.0(5) pm for Ho14Pd2.95In3, a = 955.5(1), c = 2305.1(5) pm for Er14Pd3In3, a = 950.9(1), c = 2291.6(5) pm for Tm13.90Pd3In3.10, a = 944.4(1), c = 2275.5(5) pm for Lu13.93Pd3In3.07, a = 962.9(1), c = 2343.0(5) pm for Y13.86Ir2.97In3.02, a = 967.6(1), c = 2347.8(5) pm for Y13.92Pt3.05In2.91, and Gd4RhIn-type, space group F 4̅3m, a = 1368.6(2) pm for Y4IrIn. The main structural motifs are transition metal-centered trigonal prisms of the rare earth elements which are condensed to twodimensional networks in the RE14T3In3 indides and to a three-dimensional one in Y4IrIn. The indium atoms in both structure types show segregation in the metal-rich matrix, i. e. In2 dumbbells in the RE14T3In3 indides (309 pm In2-In2 in Y13.86Ir2.97In3.02) and In4 tetrahedra (322 pm In-In) in Y4IrIn. The crystal chemical peculiarities of both structure types are discussed.

The Stannides RERhSn (RE = Ho - Yb) and ScTSn (T = Pd, Pt) - Structure Refinements and 119Sn Mössbauer Spectroscopy

2001 ◽  
Vol 56 (7) ◽  
pp. 589-597 ◽  
Author(s):  
Ratikanta Mishra ◽  
Rainer Pöttgen ◽  
Rolf-Dieter Hoffmann ◽  
Henning Trill ◽  
Bernd D. Mosel ◽  
...  
Keyword(s):  
Rare Earth ◽  
Transition Metal ◽  
Three Dimensional ◽  
Lattice Parameter ◽  
Interatomic Distances ◽  
Space Group ◽  
X Ray ◽  
Arc Melting ◽  
Rhodium Stannides ◽  
The Rare Earth

Abstract The stannides RERhSn (RE = Ho -Yb) and ScTSn (T = Pd, Pt) were prepared by reaction of the elements in sealed tantalum tubes in a high-frequency furnace, by arc-melting, or by a tin-flux technique in quartz tubes. The rhodium based stannides crystallize with the ZrNiAl type structure, space group P6̄2m. The four structures were refined from single crystal X-ray data: a = 754.5(3), c = 377.1(1) pm, wR2 = 0.0357, 233 F2 values for HoRhSn, a = 753.3(1), c = 372.16(8) pm, wR2 = 0.0721, 233 F2 values for ErRhSn, a = 753.7(3), c = 369.0(2) pm, wR2 = 0.0671,233 F2 values for TmRhSn, and a = 753.17(5), c = 366.53(4) pm, wR2 = 0.0566, 180 F2 values for YbRhSn with 14 parameters for each refinement. ScPdSn and ScPtSn adopt the HfRhSn type, a superstructure of ZrNiAl, space group P6̄2c: a = 747.5(1), c = 710.2(1) pm, for ScPdSn, and a = 738.37(9), c = 729.47(9) pm, wR2 = 0.0452,369 F2 values, 18 variables for ScPtSn. Structural motifs in these stannides are transition metal centered trigonal prisms formed by the rare earth and tin atoms. While these prisms are regular in the rhodium based stannides, significant distortions occur in ScPdSn and ScPtSn. The formation of the superstructure can be ascribed to packing reasons. The shortest interatomic distances occur between the transition metal (T) and tin atoms. These atoms form three-dimensional [FSn] networks in which the rare earth atoms fill distorted hexagonal channels. The series RERhSn displays a somewhat unique behavior. The a lattice parameter is more or less independent of the rare earth element, while the c lattice parameter shows the expected lanthanoid contraction. 119Sn Mössbauer spectroscopic data of the rhodium stannides show signals at isomer shifts varying from 1.77 to 1.82 mm/s subject to quadrupole splitting between 0.75 to 0.82 mm/s.

Rare Earth-rich Cadmium Compounds RE4TCd (T = Ni, Pd, Ir, Pt)

2008 ◽  
Vol 63 (9) ◽  
pp. 1127-1130 ◽  
Author(s):  
Falko M. Schappacher ◽  
Ute Ch. Rodewald ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Transition Metal ◽  
Single Crystal ◽  
Intermetallic Compounds ◽  
Three Dimensional ◽  
Type Structure ◽  
Space Group ◽  
X Ray ◽  
Structure Space ◽  
Cadmium Compounds

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.

Alkaline earth-gold-aluminides: synthesis and structure of SrAu3Al2, SrAu2.83Al2.17, BaAu2.89Al2.11 and BaAu7.09Al5.91

2015 ◽  
Vol 70 (12) ◽  
pp. 903-909 ◽  
Author(s):  
Birgit Gerke ◽  
Rainer Pöttgen
Keyword(s):  
Single Crystal ◽  
Alkaline Earth ◽  
Three Dimensional ◽  
Crystal Chemical ◽  
Space Group ◽  
X Ray ◽  
Type Space ◽  
Annealing Temperatures

AbstractNew alkaline earth-gold-aluminides were synthesized from the elements in sealed tantalum or quartz ampoules in muffle furnaces at maximum annealing temperatures of 1325 K. The structures were refined from single crystal X-ray diffractometer data. SrAu3Al2 crystallizes in an ordered version of the LT-SrZn5 structure: Pnma, a = 1315.9(3), b = 549.0(1), c = 684.5(3) pm, wR2 = 0.0232, 930 F2 values, 35 variables. SrAu2.83Al2.17 (a = 1065.0(2), b = 845.0(2), c = 548.1(1) pm, wR2 = 0.0416, 452 F2 values, 22 variables) and BaAu2.89Al2.11 (a = 1096.1(3), b = 835.7(3), c = 554.0(1) pm, wR2 = 0.0280, 501 F2 values, 22 variables) both adopt the BaZn5 type, space group Cmcm with Au/Al mixing on the 4c site. The gold and aluminum atoms in both types form three-dimensional networks of condensed tetrahedra with the strontium and barium atoms in large cavities. BaAu7.09Al5.91 is a new member of the NaZn13 type: Fm3̅c, a = 1257.6(2) pm, wR2 = 0.0267, 168 F2 values, 12 variables. Both the 96i and 8b sites show Au/Al mixing. The crystal chemical details are discussed.

Indides RE3T2In4 (RE = Y, Gd–Tm, Lu; T = Ni, Ru, Rh) with a ZrNiAl superstructure

2016 ◽  
Vol 71 (12) ◽  
pp. 1261-1267 ◽  
Author(s):  
Birgit Heying ◽  
Oliver Niehaus ◽  
Ute Ch. Rodewald ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Transition Metal ◽  
Transition Metals ◽  
Single Crystal ◽  
Symmetry Reduction ◽  
Type Structure ◽  
Crystal Chemical ◽  
Space Group ◽  
X Ray ◽  
Structure Space

AbstractThree series of rare earth-transition metal-indides RE3T2In4 (RE=Y, Gd–Tm, Lu; T=Ni, Ru, Rh) were synthesized from arc-melted RE3T2 precursor compounds and indium tear shot in sealed niobium ampoules using different annealing sequences. The new indides crystallize with the hexagonal Lu3Co2In4-type structure, space group P6̅. All samples were characterized on the basis of Guinier powder patterns and six structures were refined from single crystal X-ray diffractometer data. The RE3T2In4 structures are derived from the ZrNiAl type through RE/In ordering, paralleled by a symmetry reduction from P6̅2m to P6̅. This induces twinning for some of the investigated crystals. The main crystal chemical motifs of the RE3T2In4 structures are trigonal prisms of rare earth, respectively indium atoms that are filled by the transition metals.

New Indides EuAuIn2, EuPdIn4, GdRhIn2, YbRhIn4, and YbPdIn4

2000 ◽  
Vol 55 (9) ◽  
pp. 834-840 ◽  
Author(s):  
Rolf-Dieter Hoffmann ◽  
Rainer Pöttgen ◽  
Vasyl’ I. Zaremba ◽  
Yaroslav M. Kalychak
Keyword(s):  
High Frequency ◽  
Three Dimensional ◽  
Melting Furnace ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Type Space ◽  
Arc Melting ◽  
Indium Compounds ◽  
Host Lattices

New intermetallic indium compounds EuAuIn2, EuPdIn4, GdRhIn2, YbRhln4, and YbPdIn4 were obtained by reaction of the elements. GdRhIn2 was synthesized in an arc-melting furnace, while EuAuIn2, EuPdln4, YbRhIn4, and YbPdIn4 were prepared in sealed tantalum tubes in a high-frequency furnace. The five compounds were investigated by X-ray diffraction both on powders and single crystals. EuAuIn2 and GdRhIn2 adopt the MgCuAl2 type structure with space group Cmcm. Single crystal X-ray data yielded a = 468.1(2), b = 1105.5(4), c = 753.5(4) pm, wR2 = 0.096, 343 F2 values for EuAuIn2 and a = 435.0(1), b = 1013.3(3), c = 783.6(2) pm, wR2 = 0.042, 608 F2 values for GdRhIn2 with 16 variables for each refinement. The two structures may be described as gold or rhodium filled versions of the host lattices Euln2 and GdIn2 . The three-dimensional indium networks of EuAuIn2 and GdRhIn2 resemble the lonsdaleite structure. Both structures are built up from three-dimensional [Auln2] and [Rhln2] poly anions in which the europium and gadolinium atoms occupy distorted hexagonal tubes. The modulations of the In-In distances within the indium networks are compared with other MgCuAl2 type indides. EuPdIn4 and YbPdIn4 crystallize with the YNiAl4 type, space group Cmcm: a = 454.8(2), b = 1703.2(8), c = 738.0(3) pm, wR2 = 0.044, 501 F2 values for EuPdIn4 and a = 445.8(2), b = 1666.0(4), c = 747.3(2) pm, wR2 = 0.050, 711 F2 values for YbPdIn4 with 24 variables for each refinement. In contrast, YbRhln4 adopts the LaCoAl4 type, space group Pmma: a = 863.7(2), b = 422.5(1), c = 743.1(1) pm, wR2 = 0.051, 467 F2 values and 24 variables. EuPdIn4, YbPdlIn4, and YbRhIn4 too consist of three-dimensional [Pdln4] and [Rhln4] polyanions in which the europium and ytterbium atoms are located in distorted hexagonal and pentagonal channels. Common structural motifs of these indides are distorted bcc-like indium cubes which are compared with the structures of Y2CoIn8, YCoIn5, EuRh2ln8, and elemental indium. Chemical bonding in these indides 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.

Coloring variants of the Re3B type

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Stefan Seidel ◽  
Rainer Pöttgen
Keyword(s):  
Basic Structure ◽  
Crystal Chemical ◽  
Space Group ◽  
Type Space ◽  
Symmetry Reductions ◽  
Phase Precipitate ◽  
Lower Symmetry ◽  
Trigonal Prisms

Abstract The Re3B type, space group Cmcm, has boron-centered trigonal prisms as central building units and is one of the basic structure types with numerous binary and ternary representatives. The coloring of different atoms on the two crystallographically independent rhenium sites leads to a manifold of compounds with different bonding peculiarities that are rather isopointal than isotypic with the prototype. Typical compounds are the S-phase precipitate MgCuAl2, the silicide ScPt2Si or the iodide Th0.5Pb0.5I3 (PuBr3 type). Differences in size or composition might force symmetry reductions. This is discussed for YZn3 (space group Pnma) and the different coloring variants ScRhSi2 and TaNi2P which show different twists of the trigonal prisms. Striking singular representatives with lower symmetry structures are BaThBr6 (Pmma) and NbCo2B (P21/c) which allow different ordering/distortion patterns for the prisms. All these crystal chemical details are discussed on the basis of group subgroup schemes (Bärnighausen trees).

Die Röntgenstrukturanalyse von (CO)9Co3CΟΒΒr2Ν(C5)3. X-ray Structure Analysis of (CO)9Co3COBBr2N(C2H5)3

1976 ◽  
Vol 31 (3) ◽  
pp. 342-344 ◽  
Author(s):  
Volker Bätzel
Keyword(s):  
Least Squares ◽  
Structure Analysis ◽  
Reliability Index ◽  
Three Dimensional ◽  
Diagonal Matrix ◽  
Crystal Data ◽  
Block Diagonal Matrix ◽  
Fourier Methods ◽  
Space Group ◽  
X Ray

Using three dimensional X-ray data collected on a four circle diffractometer, the structure of (CO)9Co3COBBr2N(C2H5)3 was solved by Patterson and Fourier methods. Least squares refinement with a block-diagonal matrix leads to a reliability index of R = 10.7%. Crystal data: α = 13.277(6) Å, b = 10.17(1) Å, c = 9.22(2) Å; α = 91.12(6)°, β = 87.61(4)°, γ = 98.79(2)°; space group P1̅; Z = 2; V = 1229,7 Å3; Dx = 1.97 gcm-3.

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

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