Rare Earth-rich Cadmium Compounds RE23T7Cd4 (T = Co, Ni, Ru, Rh, Ir, Pt)

2009 ◽  
Vol 64 (2) ◽  
pp. 184-188 ◽  
Author(s):  
Frank Tappe ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Transition Metal ◽  
Single Crystal ◽  
Intermetallic Compounds ◽  
High Frequency ◽  
Three Dimensional ◽  
Type Structure ◽  
Interatomic Distances ◽  
X Ray ◽  
Structure Space

The rare earth-rich intermetallic compounds RE23T7CD4(RE = La-Nd, Sm, Gd, Tb; T = Co, Ni, Ru, Rh, Ir, Pt) were synthesized by melting of the elements in sealed tantalum tubes in a high frequency furnace. They crystallize with the Pr23Ir7Mg4-type structure, space group P63mc, Z = 2. The structures of La23Pt7Cd4 (a = 1025.4(2), c = 2319.5(5) pm, wR2 = 0.0425, 2587 F2, 74 variables), La23Ru6.87(1)Cd4 (a = 1015.0(2), c = 2282.8(4) pm, wR2 = 0.0383, 2459 F2, 75 variables), and Nd23Rh7Cd4 (a = 990.0(2), c = 2239.0(5) pm, wR2 = 0.0507, 2350 F2, 74 variables) were refined from single crystal X-ray diffractometer data. Central structural motifs of the RE23 T7Cd4 compounds are transition metal-centered trigonal prisms of rare earth atoms and Cd4 tetrahedra. The RE6T prisms are condensed via common edges and corners, leading to three-dimensional networks. Typical interatomic distances in the prismatic network and in the Cd4 tetrahedra are 295 - 313 pm La-Pt and 319 - 325 pm Cd-Cd, respectively (examplarily for La23Pt7Cd4)

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.

MgCuAl2-type Intermetallics REPdCd2(RE = Ce, Pr, Nd, Sm)

2012 ◽  
Vol 67 (11) ◽  
pp. 1221-1224 ◽  
Author(s):  
Michael Johnscher ◽  
Rainer Pöttgen
Keyword(s):  
Single Crystal ◽  
Intermetallic Compounds ◽  
High Frequency ◽  
Three Dimensional ◽  
Type Structure ◽  
Subsequent Annealing ◽  
Space Group ◽  
X Ray ◽  
Structure Space ◽  
Structure Factors

The cadmium-rich intermetallic compounds REPdCd2 (RE=Ce, Pr, Nd, Sm) were obtained by high-frequency melting of the elements in sealed niobium ampoules and subsequent annealing in muffle furnaces. The REPdCd2 phases crystallize with the orthorhombic MgCuAl2-type structure, space group Cmcm. The structure of NdPdCd2 was refined from single-crystal X-ray diffractometer data: a=421.9(3), b=995.4(7), c=834.5(6) pm, wR=0.0286, 451 structure factors, 16 variables. The palladium and cadmium atoms build up a three-dimensional [PdCd2] network (281 - 283 pm Pd-Cd; 298 - 335 pm Cd-Cd) in which the neodymium atoms fill cavities. They are connected to the [PdCd2] network via shorter Nd-Pd bonds of 286 pm.

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.

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.

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)

CaPtIn4 – an intergrowth variant of CaPtIn2 and indium slabs

2019 ◽  
Vol 74 (9) ◽  
pp. 693-698 ◽  
Author(s):  
Birgit Heying ◽  
Jutta Kösters ◽  
Rainer Pöttgen
Keyword(s):  
Intermetallic Compound ◽  
Single Crystal ◽  
Peritectic Reaction ◽  
Three Dimensional ◽  
Type Structure ◽  
Space Group ◽  
X Ray ◽  
Structure Space ◽  
Indium Metal

AbstractThe indium-rich intermetallic compound CaPtIn4 is formed in a peritectic reaction of CaPtIn2 and indium metal at T = 670 K (14 days annealing). CaPtIn4 crystallizes with the YNiAl4-type structure, space group Cmcm, which was refined from single crystal X-ray diffractometer data: a = 446.3(5), b = 1659.50(18), c = 756.8(8) pm, wR2 = 0.0646, 640 F2 values and 24 variables. Geometrically one can describe the CaPtIn4 structure as an intergrowth variant of CaPtIn2 (MgCuAl2 type) and indium slabs. The three-dimensional [PtIn4] polyanionic network shows short Pt–In distances of 269–280 pm and a broader range of In–In distances (304–378 pm) within substantially distorted In@In8 cubes.

Copper-rich Intermetallic Compounds RECu9Cd2(RE = La, Ce, Pr, Nd) with YNi9In2-type Structure

2012 ◽  
Vol 67 (11) ◽  
pp. 1225-1228 ◽  
Author(s):  
Michael Johnscher ◽  
Rainer Pöttgen
Keyword(s):  
Single Crystal ◽  
Intermetallic Compounds ◽  
Induction Furnace ◽  
Three Dimensional ◽  
Pair Formation ◽  
Type Structure ◽  
X Ray Diffraction ◽  
X Ray

The YNi9In2-type copper-rich compounds RECu9Cd2 (RE=La, Ce, Pr, Nd) were synthesized directly from the elements in sealed niobium ampoules in an induction furnace and were characterized by powder X-ray diffraction. The structure of PrCu9Cd2 was refined from single-crystal Xray diffractometer data: P4/mbm, a=849.0(3), c=498.2(3) pm, wR2=0.0418, 374 F2 values, 23 variables. The structure has two striking polyhedral motifs: Pr@Cu16Cd4 and Cu2@Cu8Cd4. The packing of these polyhedra describes the whole structure. The copper and cadmium atoms build up a three-dimensional [Cu9Cd2] network with broader ranges of Cu-Cu (246 - 274 pm) and Cu-Cd (272 - 288 pm) distances. The cadmium atoms show segregation through pair formation with Cd-Cd distances of 288 pm.

Dy3Co6Sn5 – a New Stannide with an Ordered La3Al11 Type Structure

1995 ◽  
Vol 50 (2) ◽  
pp. 175-179 ◽  
Author(s):  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Transition Metal ◽  
Single Crystal ◽  
Crystal Chemistry ◽  
Title Compound ◽  
Type Structure ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Arc Melting ◽  
New Type

The title compound has been obtained by arc-melting of the elemental components and subsequent annealing at 800 °C. It crystallizes in the orthorhombic space group Immm, a = 430.3(1), b = 1235.0(2), c = 967.6(3) pm, V = 0.5142(2) nm3, Z = 2. The structure has been determined from single-crystal X-ray data and refined to R = 0.0181 for 747 F2 values and 28 variables. It is of a new type and can be described as a ternary ordered version of the binary La3Al11-type structure. Dy3Co6Sn5 is built up from DyCo2Sn2 and DyCo2Sn slabs with ThCr2Si2 and Cu3Au-like atomic arrangements, respectively. Its crystal chemistry is compared with that of structurally related rare earth transition metal gallides.

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.

Platinum-Germanium Ordering in the Germanides REPtGe with the Heavy Rare Earth Elements

2009 ◽  
Vol 64 (4) ◽  
pp. 383-387 ◽  
Author(s):  
Ute Ch. Rodewald ◽  
Birgit Heying ◽  
Rolf-Dieter Hoffmann ◽  
Dirk Niepmann ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Single Crystal ◽  
Three Dimensional ◽  
Type Structure ◽  
Crystal Chemical ◽  
Heavy Rare Earth ◽  
Structure Space ◽  
Arc Melting ◽  
Heavy Rare Earth Elements

The equiatomic germanides REPtGe with the heavy rare earth elements (RE) have been reinvestigated with respect to platinum-germanium ordering. The compounds were prepared by arc-melting of the elements followed by annealing for two weeks at 1070 K. The REPtGe germanides crystallize with the TiNiSi-type structure, space group Pnma. The structures of ErPtGe (a = 692.01(5), b = 432.03(4), c = 753.19(5) pm, wR2 = 0.0523, 435 F2, 20 variables) and the new germanide LuPtGe (a = 683.1(1), b = 429.2(1), c = 750.3(1) pm, wR2 = 0.0696, 358 F2, 20 variables) have been refined from single crystal diffractometer data. These structures exhibit three-dimensional [PtGe] networks with strong Pt-Ge intra- (251 - 255 pm in LuPtGe) and weaker interlayer (272 pm in LuPtGe) interactions. The crystal chemical peculiarities of the whole REPtGe series are briefly discussed.

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