Notizen: Sodium Metaperrhenate, NaReO4: High Pressure Synthesis of Single Crystals and Structure Refinement

1995 ◽  
Vol 50 (9) ◽  
pp. 1417-1418 ◽  
Author(s):  
Alexandra Atzesdorfer ◽  
Klaus-Jürgen Range
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Single Crystals ◽  
Sodium Nitrate ◽  
Structure Refinement ◽  
Type Structure ◽  
Space Group ◽  
High Pressure Synthesis ◽  
High Pressure High Temperature ◽  
Pressure Synthesis

Single crystals of sodium metaperrhenate, NaReO4, have been obtained by oxidation of rhenium metal with sodium nitrate under high pressure- high temperature conditions (modified Belttype apparatus, 4 kbar, 400 °C, Au-capsules). The crystals are tetragonal, space group I41/a, with a = 5.3654(4), c = 11.732(2) Å and Z = 4. The structure was refined to R - 0.026, Rw = 0.013 for 382 unique, absorption-corrected reflections. The scheelite-type structure for NaReO4, proposed by Beintema in 1937, could be confirmed. It consists of isolated ReO4 tetrahedra (Re-O= 1.728(2) Å ), connected by NaOs dodecahedra (<Na- O > = 2.582(2) Å).

scholarly journals Multianvil High-Pressure/High-Temperature Synthesis and Characterization of multiferroic HP-Co3TeO6

2021 ◽  
Author(s):  
Gunter Heymann ◽  
Elisabeth Selb ◽  
Toni Buttlar ◽  
Oliver Janka ◽  
Martina Tribus ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Type Structure ◽  
Synthesis And Characterization ◽  
Temperature Synthesis ◽  
Space Group ◽  
Crystal System ◽  
High Temperature Synthesis ◽  
High Pressure High Temperature

By high-pressure/high-temperature multianvil synthesis a new high-pressure (HP) phase of Co3TeO6 was obtained. The compound crystallizes in the acentric trigonal crystal system of the Ni3TeO6-type structure with space group R3...

scholarly journals High-Pressure Synthesis, Crystal Structure, and Photoluminescence Properties of β-Y2B4O9:Eu3+

Inorganics ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 136
Author(s):  
Fuchs ◽  
Schröder ◽  
Heymann ◽  
Jüstel ◽  
Huppertz
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
High Temperature ◽  
Single Crystal ◽  
Photoluminescence Properties ◽  
Triclinic Space Group ◽  
Space Group ◽  
High Pressure High Temperature ◽  
Temperature Experiment ◽  
Pressure Synthesis

A high-pressure/high-temperature experiment at 7.5 GPa and 1673 K led to the formation of the new compound βY2B4O9. In contrast to the already known polymorph αY2B4O9, which crystallizes in the space group C2/c, the reported structure could be solved via single-crystal Xray diffraction in the triclinic space group P1 (no. 2) and is isotypic to the already known lanthanide borates βDy2B4O9 and βGd2B4O9. Furthermore, the photoluminescence of an europium doped sample of βY2B4O9:Eu3+ (8%) was investigated.

Hochdrucksynthese und Strukturverfeinerung von SrVO3, Sr2VO4 und Sr3V2O7 / High-Pressure Synthesis and Structure Refinement of SrVO3, Sr2VO4, and Sr3V2O7

1991 ◽  
Vol 46 (10) ◽  
pp. 1315-1318 ◽  
Author(s):  
Klaus-Jürgen Range ◽  
Franz Rau ◽  
Ulrich Klement
Keyword(s):  
High Pressure ◽  
Single Crystals ◽  
Crystal Structures ◽  
Structure Refinement ◽  
Type I ◽  
High Pressure Synthesis ◽  
Pressure Synthesis ◽  
Perovskite Type ◽  
Type Apparatus

Single crystals of SrVO3, Sr2VO4 and Sr3V2O7 have been obtained by high-pressure reactions in a modified belt-type apparatus. The crystal structures, refined from diffractometer data, are as follows: SrVO3, perovskite type, Pm3̄m, a = 3.8408(3) Å, R = 0.017, Rw = 0.018, composition from occupancy refinement of oxygen positions SrVO2.93(2); Sr2VO4, K2NiF4 type, I 4/mmm, a = 3.837(1), c = 12.569(1) Å, R = 0.014, Rw = 0.017; Sr3V2O7, Sr3Ti2O7 type, I 4/mmm, a = 3.839(1), c = 20.262(2) Å, R = 0.020, Rw = 0.029.

β-PtO2: High pressure synthesis of single crystals and structure refinement

1987 ◽  
Vol 22 (11) ◽  
pp. 1541-1547 ◽  
Author(s):  
K.-J. Range ◽  
F. Rau ◽  
U. Klement ◽  
A.M. Heyns
Keyword(s):  
High Pressure ◽  
Single Crystals ◽  
Structure Refinement ◽  
High Pressure Synthesis ◽  
Pressure Synthesis

scholarly journals Die Kristallstruktur von TIZnPO4 und TIZnAsO4 / The Crystal Structure of TIZnPO4 and TIZnAsO4

1994 ◽  
Vol 49 (9) ◽  
pp. 1282-1288 ◽  
Author(s):  
Martina Andratschke ◽  
Klaus-Jürgen Range ◽  
Claudia Weigl ◽  
Ulrike Schießl ◽  
Franz Rau
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Single Crystals ◽  
Structure Type ◽  
Monoclinic System ◽  
Space Group ◽  
High Pressure Synthesis ◽  
Pressure Synthesis ◽  
Derivatives Of ◽  
Type Apparatus

Single crystals of the title com pounds were obtained by high pressure synthesis in a modified Belt type apparatus. The compounds crystallize in the monoclinic system (space group P21) with a = 8.732(2), b = 5.468(1), c = 8.841(2) Å, β = 90.61(2)° for TlZnPO4 and a = 8.921(3), b = 5.631(1), c = 8.958(3) Å, β = 91.03(2)° for TlZnAsO4, Z = 4. The structures were refined from diffractom eter data to R = 0.072, Rw = 0.050 for 3700 (TlZnPO4) and to R = 0.093, Rw = 0.067 for 3943 (TlZnAsO4) independent absorption corrected reflections. The compounds are isotypic and belong to the “stuffed derivatives" of the Icmm structure type with a (ZnXO4)- network of alternating corner linked ZnO4 and XO4 tetrahedra (X = P, As) forming channels of six-membered rings in the direction of the a axis. These cavities contain two crystallographically independent Tl cations in an irregular coordination by eight nearest oxygen atoms

scholarly journals High-pressure synthesis, structure, phase relation of polar LiNbO3-type ZnTiO3

2014 ◽  
Vol 70 (a1) ◽  
pp. C1348-C1348
Author(s):  
Yoshiyuki Inaguma ◽  
Akihisa Aimi ◽  
Yuichi Shirako ◽  
Daichi Sakurai ◽  
Daisuke Mori ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Spontaneous Polarization ◽  
Second Order ◽  
Type Structure ◽  
First Principles Calculation ◽  
Stable Phase ◽  
High Pressure Synthesis ◽  
Pressure Synthesis ◽  
Perovskite Type

Ferroelectricity, piezoelectricity, pyroelectricity, and second-order nonlinear optical behavior are technologically important. Because these properties are attributable to the noncentrosymmetric (NCS) structure[1], the search for materials exhibiting such characteristics must begin with a search of NCS materials. Among them, LiNbO3-type (LN-type) compounds with a chemical formula of ABX3 exhibit NSC structures with hexagonal polar space group R3c whose BX6 octahedra three-dimensionally share their corners the same as perovskite-type compounds[2]. In LN-type compounds, the A cation - B cation repulsion directs the spontaneous polarization along c-axis(Fig. 1). Therefore, we might find attractive functional properties by the selection of constituent ions based on their having a naturally occurring polar LN-type structure attributable to the cation-cation repulsion. With the ideas mentioned above, we have investigated the high-pressure synthesis and characterization of novel LN-type oxides such as ZnSnO3, PbNiO3, CdPbO3 as well as known MnMO3 (M = Ti, Sn). Recently, we have successfully synthesized a polar LN-type titanate ZnTiO3 (LN-ZTO) under high pressure and high temperature [3]. The first principles calculation indicates that LN-ZTO is a meta-stable phase obtained by the transformation in the decompression process from the perovskite-type phase, which is stable at high pressure and high temperature. The Rietveld structural refinement reveals that LN-ZTO exhibits greater intra-distortion of the TiO6 in LN-ZTO than that of the SnO6 in LN-type ZnSnO3 (LN-ZSO). The estimated spontaneous polarization are greater than those of LN-ZSO, which is attributed to the great displacement of Ti along c-axis and the greater Born effective charge of Ti (+6.1) than that of Sn (+4.1). Furthermore, the spontaneous polarization of LN-ZTO is greater than that of LiNbO3, indicating that LN-ZTO, like LiNbO3, is a candidate ferroelectric material with high performance. The second harmonic generation (SHG) response of LN-ZTO is 24 times greater than that of LN-ZSO. The findings indicate that the intra-octahedral distortion, spontaneous polarization, and SHG response are caused by the stabilization of the polar LN-type structure and reinforced by the second-order Jahn-Teller effect attributable to the orbital interaction between oxygen ions and d0 ions such as Ti4+. We also discuss the relationship between the intra-distortion of BO6 and polarity in several LN-type oxides.

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