Quaternary Equiatomic Compounds LnZnSbO (Ln = La - Nd, Sm) with ZrCuSiAs-Type Structure

1997 ◽  
Vol 52 (12) ◽  
pp. 1467-1470 ◽  
Author(s):  
Petra Wollesen ◽  
Joachim W. Kaiser ◽  
Wolfgang Jeitschko
Keyword(s):  
Zinc Oxide ◽  
Single Crystal ◽  
Chemical Bonding ◽  
Type Structure ◽  
Variable Parameters ◽  
X Ray ◽  
Structure Factors ◽  
Cold Pressed

Abstract The five compounds LnZnSbO (Ln = La - Nd, Sm) were prepared by annealing cold-pressed pellets of the lanthanoids, zinc oxide, and antimony, or by reacting these components in a NaCl/KCl flux. They crystallize with the tetragonal ZrCuSiAs type structure, which was refined from single-crystal X-ray data of CeZnSbO : P 4/nmm, a = 419.76(4), c = 947.4(1) pm, Z = 2, R = 0.022 for 165 structure factors and 12 variable parameters. Chemical bonding in this and the formally isotypic compound CeZn1-xSb2 is briefly discussed.

Quaternary Equiatomic Manganese Pnictide Oxides AMnPO (A = La-Nd, Sm, Gd-Dy), AMnAsO (A = Y, La-Nd, Sm, Gd-Dy, U), and AMnSbO (A = La-Nd, Sm, Gd) with ZrCuSiAs Type Structure

1997 ◽  
Vol 52 (5) ◽  
pp. 560-564 ◽  
Author(s):  
Andre T. Nientiedt ◽  
Wolfgang Jeitschko ◽  
Peter G. Pollmeier ◽  
Markus Brylak
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Single Crystal ◽  
Chemical Bonding ◽  
Type Structure ◽  
Variable Parameters ◽  
X Ray ◽  
Structure Factors ◽  
The Rare Earth

Abstract The 24 title compounds were prepared in well crystallized form by reaction of the rare earth elements (or uranium, respectively), manganese, the pnictide components, and MnO2 in a NaCl/KCl flux. They crystallize with the tetragonal ZrCuSiAs type structure (P4/nmm, Z = 2), which has been refined from single-crystal X-ray data of NdMnPO (a = 398.9(1), c = 867.4(1) pm, R = 0.026), NdMnAsO (a = 404,9(2), c = 889.3(4) pm, R = 0.025), and NdMnSbO (a = 416.5(1), c = 946.2(2) pm, R = 0.021) for 107, 190, and 124 structure factors, respectively, and 11 variable parameters each. Chemical bonding in these compounds is briefly discussed.

Quaternary Phosphide Oxides Pr3Cu4P4O2–x and Sm3Cu4P4O2–x with Ordered Zr3Cu4Si6-Type Structure

2002 ◽  
Vol 57 (2) ◽  
pp. 165-170 ◽  
Author(s):  
Joachim W. Kaiser ◽  
Wolfgang Jeitschko
Keyword(s):  
Single Crystal ◽  
Chemical Bonding ◽  
Empirical Formula ◽  
Type Structure ◽  
Formula Unit ◽  
Variable Parameters ◽  
Space Group ◽  
X Ray ◽  
Structure Space ◽  
Structure Factors

The compounds Ln3Cu4P4O2-χ (Ln = Pr, Sm) were prepared by annealing the elemental components in a NaCl/KCl flux. They crystallize with an ordered Zr3Cu4Si6-type structure (space group I4/mmm, Z = 2), which was refined from single-crystal X-ray data for both compounds; Pr3Cu4P4O2-χ: a = 397.8(1), c = 2658.7(3) pm, R = 0.046 for 235 structure factors and 19 variable parameters; Sm3Cu4P4O2-χ: a = 392.8(1), c = 2643.6(3) pm, R = 0.057 for 145 F values and 19 variables. The refinements showed partial occupancy for the oxygen positions resulting in approximately 1.5 oxygen atoms per formula unit. Half of the phosphorus atoms form pairs with typical two-electron bond distances of 222.8(4) and 221.7(8) pm, respectively. Using oxidation numbers chemical bonding in these phosphide oxides can be rationalized with the formula (Ln+3)3(Cu+1)4(P-P)-4(P-3)2(O-2)1.5. Hence, the empirical formula may also be doubled (Ln6Cu8P8O3), and the compounds are expected to be semiconducting.

The Crystal Structures of Re2Al, Re4Al11, and ReAl6

1993 ◽  
Vol 48 (12) ◽  
pp. 1767-1773 ◽  
Author(s):  
Sabine Niemann ◽  
Wolfgang Jeitschko
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Type Structure ◽  
Variable Parameters ◽  
X Ray ◽  
Lattice Constants ◽  
Structure Factors ◽  
Pauli Paramagnetism

Well-crystallized samples of the rhenium aluminides Re4Al11 and ReAl6 were obtained by reaction of rhenium with an excess of aluminum. Re4Al11 was found to be isotypic with Mn4Al11. The MnAl6 type structure of ReAl6 was confirmed. The crystal structures of both compounds were refined from single-crystal X-ray data. Re4Al11:P1̄, Z = 1, a = 516.0(1) pm, b = 896.3(2) pm, c = 516.9(1) pm, a = 90.44(1)°, β = 99.76(1)°, γ = 105.17(1)°, V = 0.2271 nm3, R = 0.036 for 2315 structure factors and 74 variable parameters. ReAl6: Cmcm, Z = 4, a = 761.0(1) pm, b = 660.5(1) pm, c = 903.4(1) pm, V = 0.4541 nm3, R = 0.013 for 711F values and 23 variables. In both structures the rhenium atoms have ten aluminum neighbors at distances from 245 to 277 pm. The Al-Al distances cover the whole range from 251 to 362 pm rather continuously. The previously reported compound Re2Al with the tetragonal MoSi2-type structure has the lattice constants a = 298.1(1) pm, c = 958.4(4) pm, V = 0.08519 nm3. ReAl6 shows Pauli-paramagnetism.

New Magnesium Compounds RE2Cu2Mg (RE = Y, La -Nd, Sm, Gd -Tm, Lu) with Mo2FeB2 Type Structure

2001 ◽  
Vol 56 (3) ◽  
pp. 239-244 ◽  
Author(s):  
Ratikanta Mishra ◽  
Rolf-Dieter Hoffmann ◽  
Rainer Pöttgen
Keyword(s):  
Single Crystal ◽  
Chemical Bonding ◽  
High Frequency ◽  
Type Structure ◽  
Variable Parameters ◽  
X Ray ◽  
Structure Space ◽  
Magnesium Compounds ◽  
Sample Chamber ◽  
Extended Hückel Calculations

Abstract The title compounds were synthesized by reaction of the elements in sealed tantalum tubes in a water-cooled sample chamber in a high-frequency furnace. These magnesium intermetallics crystallize with the tetragonal Mo2FeB2 type structure, space group P4/mbm. The lattice pa­ rameters of all compounds were refined from X-ray powder data. Single crystal X-ray data yielded a = 792.09(6), c = 396.31(8) pm, wR2 = 0.0396, 315 F2 values for La2Cu2Mg, a = 778.30(5), c = 384.04(5) pm, wR2 = 0.0954, 214 F2 values for Nd2Cu2Mg, and a = 762.65(5), c = 374.09(3) pm, wR2 = 0.0566, 186 F2 values for Y2Cu2Mg with 12 variable parameters for each refinement. The RE2Cu2Mg structures can be described as an intergrowth of distorted A1B2 and CsCl related slabs of compositions RECu2 and REMg. Chemical bonding in La2Cu2Mg was investigated on the basis of extended Hückel calculations and compared to isotypic La2Cu2ln. This structure was also refined from single crystal X-ray data: P4/mbm, a = 780.8(2), c = 400.1(2) pm, wR2 = 0.0351, 211 F2 values and 12 variable parameters.

The Thorium Transition Metal Borides Th2TB10 (T = Fe, Co, Ni) with a Structure Very Similar to that of CaB6

1995 ◽  
Vol 50 (8) ◽  
pp. 1195-1199 ◽  
Author(s):  
Thomas Konrad ◽  
Wolfgang Jeitschko
Keyword(s):  
Transition Metal ◽  
Single Crystal ◽  
Structure Type ◽  
Crystal Data ◽  
Variable Parameters ◽  
X Ray ◽  
Arc Melting ◽  
Structure Factors ◽  
Metal Borides ◽  
Cold Pressed

The title compounds have been prepared by arc-melting cold-pressed pellets of the elemental components. They crystallize with a new structure type, which was determined from singlecrystal X-ray diffractometer data of Th2NiB10: Pbam, a = 564.6(2) pm, b = 1120.4(3) pm, c = 417.3(1) pm, Z = 2, R = 0.020 for 748 structure factors and 25 variable parameters. The structures of Th2FeB10 (a = 562.7(1) pm, b = 1126.1(3) pm, c = 418.3(2) pm) and Th2CoB10 (a = 562.4(1) pm, b = 1122.8(2) pm, c = 418.5(1) pm) were refined from single-crystal data to residuals of 0.025 (921 F values) and 0.032 (911 F values). The lattice of these ternary borides may be derived from that of ThB6 (Th2B12) with the cubic CaB6 type structure by replacing two of the linking boron atoms of adjacent B6 octahedra by a transition metal atom.

Dimorphic ThNi2P2 with BaCu2S2 and CaBe2Ge2 Type Structure

1994 ◽  
Vol 49 (8) ◽  
pp. 1074-1080 ◽  
Author(s):  
Jörg H. Albering ◽  
Wolfgang Jeitschko
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Crystal Structures ◽  
Type Structure ◽  
Variable Parameters ◽  
Higher Symmetry ◽  
X Ray ◽  
Coordination Numbers ◽  
Structure Factors ◽  
High Temperature Form

Two modifications of ThNi2P2 were prepared in a tin flux at 850 °C (α-ThNi2P2) and 1000 °C (β-ThNi2P2). The crystal structures of both modifications were refined from single­crystal X-ray data. α-ThNi2P2 (BaCu2S2 type structure): Pnma. a = 819.69(5), b = 394.28(3), c = 981.54(7) pm. R = 0.028 for 32 variables and 654 structure factors: β-ThNi2P2 (CaBe2Ge2 type structure): P4/nmm, a = 408.5(1), c = 908.0(3) pm, R = 0.033 for 15 variable parameters and 261 F values. Although the two structures are closely related, they can be transformed into each other only by a reconstructive phase transformation. The differences and similari­ties of the two structures are discussed. The high temperature form has higher symmetry, a smaller number of variable positional parameters, and a tendency for higher coordination numbers.

Er5Re2C7, Tm5Re2C7, and Lu5Re2C7 with Sc5Re2C7 Type, and Yb2ReC2 with Pr2ReC2 Type Structures

1997 ◽  
Vol 52 (2) ◽  
pp. 231-236 ◽  
Author(s):  
R. Pöttgen ◽  
K. H. Wachtmann ◽  
W. Jeitschko ◽  
A. Lang ◽  
T. Ebel
Keyword(s):  
Magnetic Susceptibility ◽  
Bond Length ◽  
High Frequency ◽  
Annealing Process ◽  
Type Structure ◽  
The Other ◽  
Variable Parameters ◽  
X Ray ◽  
Arc Melting ◽  
Structure Factors

Abstract Er5Re2C7, Tm5Re2C7, and Lu5Re2C7 were prepared by arc-melting of the elemental components and subsequent annealing at 800 °C. Er5Re2C7 forms only after the annealing process, whereas the other two carbides were already present in the as cast samples. They crystallize with a Sc5Re2C7 type structure, which was refined from single-crystal X-ray data of Lu5Re2C7: Cmmm, a = 791.44(5), b = 1418.08(8), c = 332.79(2) pm, Z = 2, R = 0.037 for 544 structure factors and 21 variable parameters. The structure contains linear centrosymmetric C3 units with a C-C bond length of 133(2) pm and isolated carbon atoms in octahedral coordination of four lutetium and two rhenium atoms. The rhenium atoms within the two-dimensionally infinite polymeric sheets [Re2C4]n are electronically saturated as is indicated by the diamagnetism and the semiconductivity of this carbide. Yb2ReC2 was prepared by reacting the elements in a sealed tantalum tube with a high-frequency furnace. It crystallizes with a Pr2ReC2 type structure: Pnma, a = 645.91(6), b = 498.64(6), and c = 966.05(6) pm. Magnetic susceptibility measurements indicate the ytterbium atoms to be trivalent in this compound.

Ternary Intermetallic Compounds LnMn2Al10 (Ln = Y, La-Nd, Sm, Gd-Dy) and LnRe2Al10 (Ln = Ce, Pr, Sm) with CaCr2Al10-Type Structure

1998 ◽  
Vol 53 (7) ◽  
pp. 673-678 ◽  
Author(s):  
Verena M.T. Thiede ◽  
Wolfgang Jeitschko
Keyword(s):  
Transition Metal ◽  
Type Structure ◽  
Variable Parameters ◽  
X Ray ◽  
Metal Atoms ◽  
Transition Metal Atoms ◽  
Structural Relationships ◽  
Structure Factors ◽  
Ternary Intermetallic Compounds ◽  
First Time

Abstract The twelve title compounds have been prepared for the first time. Their CaCr2Al10-type structure (P4/nmm, Z = 4) was refined from single-crystal X-ray data for the three representatives TbMnAl10 (a = 1274.3(2) pm, c = 511.4(2) pm, R = 0.025 for 680 structure factors F and 43 variable parameters V), CeRe2Al10 (a = 1295.5(5) pm, c = 517.2(4) pm, R = 0.054 for 810 F and 46 V), and SmRe2Al10 (a = 1291.5(2) pm, c = 516.5(1) pm, R = 0.021 for 622 F and 46 V). The atomic positions of the lanthanoid and transition metal atoms are fully occupied. Significant deviations from the full occupancies were observed for two aluminum sites in TbMn2Al10 and for all five aluminum sites of the two rhenium-containing compounds, resulting in the compositions TbMn2Al9.63(2), CeRe2Al9.52(8), and SmRe2Al9.16(9). The cell volume of CeRe2Al10 and to a smaller extent also that of CeMn2Al10 indicate mixed or intermediate +III/+IV valencies of the cerium atoms in these compounds. The structural relationships between the three closely related body-centered tetragonal structures of ThMn12, CeMniAl8, DyFe6Al6 and the primitive tetragonal structure of CaCr2Al10 are briefly discussed.

Notizen: Synthesis and Structure of YbPdSn2

2001 ◽  
Vol 56 (4-5) ◽  
pp. 446-448 ◽  
Author(s):  
Dirk Kußmann ◽  
Rainer Pöttgen
Keyword(s):  
Single Crystal ◽  
High Frequency ◽  
Type Structure ◽  
Crystal Data ◽  
Variable Parameters ◽  
X Ray

New ternary stannide YbPdSn2 was synthesized from the elements in a sealed tantalum tube in a high-frequency furnace. YbPdSn2 was characterized through X-ray powder and single crystal data: Cmcm, a = 442.4(2), b = 1108.6(3), c = 738.4(2) pm, wR2 = 0.0450, 317 F2 values, and 16 variable parameters. YbPdSn2 crystallizes with the MgCuAl2 type structure, a ternary ordered variant of the Re3B type. The tin sublattice of YbPdSn2 corresponds to a distorted lonsdaleitelike arrangement with Sn-Sn distances varying from 303 to 336 pm.

Ternary Antimonides LnTSb3 with Ln = La-Nd, Sm and T = V, Cr

1995 ◽  
Vol 50 (6) ◽  
pp. 899-904 ◽  
Author(s):  
Markus Brylak ◽  
Wolfgang Jeitschko
Keyword(s):  
Transition Metal ◽  
Single Crystal ◽  
Structure Type ◽  
Variable Parameters ◽  
X Ray ◽  
Metal Site ◽  
Metal Atoms ◽  
Transition Metal Atoms ◽  
Structure Factors ◽  
Infinite Strings

The title compounds were prepared by reaction of the elemental components. They crystallize in a new structure type, which was determined from single-crystal X -ray data of CeCrSb3: Pbcm, a = 1310.8(3), b = 618.4(1), c = 607.9(1) pm, Z = 4, R = 0.029 for 648 structure factors and 32 variable parameters. The structure of the antimonide CeVSb3 is isotypic: a = 1319.0(2), b = 623.92(8), c = 603.03(8) pm , R = 0.041 for 477 structure factors and 32 variables. The transition metal site and one of the three antimony sites were found to have partial occupancies resulting in the exact compositions CeV0,91(1)Sb2,916(4) and CeCr0,901(9)Sb2,909(4). The structures contain fractional Sb -Sb bonds with distances varying between 301,5 and 316.4 pm. The transition metal atoms have octahedral antimony coordination. These TSb6 octahedra share faces resulting in linear infinite strings with V - V and Cr - Cr bond distances of 301.5 and 304.0 pm, respectively. The structure of these com pounds contains building elements, which are also found in antimonides with ThCr2Si2, CaBe2Ge2, and HfCuSi2 type structures.

Sign in / Sign up

Export Citation Format

Share Document