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

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.

2007 ◽  
Vol 62 (12) ◽  
pp. 1574-1580 ◽  
Author(s):  
Roman Zaremba ◽  
Ute Ch. Rodewald ◽  
Rainer Pöttgen

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.


2019 ◽  
Vol 74 (9) ◽  
pp. 693-698 ◽  
Author(s):  
Birgit Heying ◽  
Jutta Kösters ◽  
Rainer Pöttgen

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.


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.


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.


1996 ◽  
Vol 51 (6) ◽  
pp. 806-810 ◽  
Author(s):  
Rainer Pöttgen

Abstract EuPdSn and EuPtSn were prepared from the elements in tantalum tubes at 1070 K and investigated by X-ray diffraction on both powder as well as single crystals. They crystallize with the TiNiSi type structure of space group Pnma and with Z = 4 formula units per cell. Both structures were refined from single-crystal diffractometer data: a = 751.24(9), b = 469.15(6), c = 804.31(9) pm, V = 0.2835(1) nm3 for EuPdSn, and a = 753.38(7), b = 467.72(4), c = 793.08(7) pm, V = 0.2795(1) nnr for EuPtSn. The structures consist of three-dimensional [PdSn] and [PtSn] polyanionic networks in which the europium atoms are embedded. The crystal chemistry of these stannides is briefly discussed


1995 ◽  
Vol 50 (9) ◽  
pp. 1377-1381 ◽  
Author(s):  
Olaf Reckeweg ◽  
H.-Jürgen Meyer

AbstractThe new compounds A4[Nb6Cl12(N3)6](H2O)2 (A = Rb, Cs) were synthesized from In4[Nb6Cl12Cl6] by substituting six terminal Cl ligands and the In+ ions in methanolic solution. An X-ray structure refinement was performed on single-crystal data of Rb4[Nb6Cl12(N3)6](H2O)2 (1) (space group P1̄, Z = 1, a = 912.5(1) pm, b = 937.2(1) pm, c = 1062.0(1) pm, α = 96.88(2)°, β = 101.89(1)°, γ = 101.44(2)°) and Cs4[Nb6Cl12(N3)6](H2O)2 (2) (space group PI, Z = 1, a = 920.9(5) pm, b = 947.9(7) pm, c = 1091.8(7) pm, α = 96.89(6)°, β = 103.35(5)°, γ = 101.60(5)°. Each of the centrosymmetric [Nb6Cl12(N3)6]4- ions of the isotypic compounds contains six terminal azide groups at the corners of the octahedral niobium cluster (d̄Nb-N = 226(1) pm (1), 225(1) pm (2), bond angles Nb-N-N 120-127°). The [Nb6Cl12(N3)6]4- ions are linked via Rb-N and Rb-Cl interactions of the Rb+ ions to form a three-dimensional structure. Crystals of the compounds react explosively on heating or mechanical pressure.


1994 ◽  
Vol 9 (2) ◽  
pp. 84-86 ◽  
Author(s):  
J. Ll. Tamarit ◽  
N. B. Chanh ◽  
P. Négrier ◽  
D. O. López ◽  
M. Barrio ◽  
...  

By means of X-ray single crystal Weissenberg photographs, the crystal of the low-temperature solid form of 2-methyl-2-nitro-propanol, (CH3)2C(NO2)(CH2OH), has been determined and found to be of the monoclinic type, space group P21/c. The cell constants were refined from X-ray powder diffraction data: a=6.195(3) Å, b=19.116(7) Å, c=16.598(7) Å, and β = 90.12(2)° with Z = 12. The indexed pattern at 293 K is given.


2017 ◽  
Vol 72 (8) ◽  
pp. 603-607 ◽  
Author(s):  
Daniel Voßwinkel ◽  
Rainer Pöttgen

AbstractSingle crystals of Sc2Pt9Si3 have been obtained from an arc-melted and inductively annealed sample of the starting composition Sc:4Pt:2Si. The Sc2Pt9Si3 structure (Tb2Pt9Ge3 type, space group C2/c) was refined from single crystal X-ray diffractometer data: a=1303.4(1), b=749.9(1), c=973.5(1), β=116.44(1)°, wR2=0.0731, 1643 F2 values and 67 variables. The structure contains three basic coordination polyhedra Sc@Pt11, Si1@Pt8 and Si2@Pt8 which show a simple condensation pattern avoiding direct Sc–Si and Si–Si bonding.


1996 ◽  
Vol 51 (5) ◽  
pp. 751-753 ◽  
Author(s):  
Gabriele Weber ◽  
Klaus-Jürgen Range

The zircon-type structure of calcium chromate( VI), CaCrO4, has been confirmed and refined from single-crystal X-ray data. The compound crystallizes tetragonaly, space group I41/amd, with a = 7.222(2), c = 6.285(1) Å, c/a = 0.8703 and Z = 4. The structure comprises isolated, slightly distorted CrO4 tetrahedra ( C r-O = 1.646(3) Å ) which are connected with CaO8 dodecahedra (<Ca-O> = 2.556 Å) by edge- and corner-sharing. The three-dimensional framework thus created contains rather large holes which are, however, empty in the case of CaCrO4


2000 ◽  
Vol 55 (11) ◽  
pp. 1025-1030 ◽  
Author(s):  
Yaroslav V. Galadzhun ◽  
Vasyl' I. Zaremba ◽  
Holger Piotrowski ◽  
Peter Mayer ◽  
Rolf-Dieter Hoffmann ◽  
...  

The ternary indides ScPtln, TbPtln, and HoPtln were synthesized by reaction of the elements in an arc-melting furnace and subsequent annealing for four weeks. ScPtln and HoPtln are reported here for the first time. The three indides crystallize with the hexagonal ZrNiAl structure, a ternary ordered version of the Fe2P type, space group P6̄2m. Single crystal X-ray data yielded a = 754.6(1), c = 348.31(8) pm, wR2 = 0.0390, 177 F2 values for ScPtln, a = 759.3(1), c = 387.6(1) pm, wR2 = 0.0576, 183 F2 values for TbPtln, and a = 758.13(1), c = 381.62(1) pm, wR2 = 0.0530, 239 F2 values for HoPtln with 14 variable parameters for each refinement. Striking structural motifs of these intermetallics are short Pt-In distances (270 - 286 pm) within the three-dimensional [Ptln] polyanions which are composed of Pt(2)In6 trigonal prisms and trigonal planar P t(l)In3 units. The platinum-indium substructure of ScPtln is discussed in comparison with the various platinum-indium networks in the structures of Ptln2, Pt3In7, SrPtln, Sr2Pt3ln4, SrPtIn2, LaPtIn3, and PtIn7Fi3.


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