Hochdrucksynthese und Kristallstruktur von Kalium- und Rubidiumdiwolframat(VI), K2W2O7 und Rb2W2O7 / High-Pressure Synthesis and Crystal Structure of Potassium and Rubidium Ditungstate(VI), K2W2O7 und Rb2W2O7

1990 ◽  
Vol 45 (2) ◽  
pp. 107-110 ◽  
Author(s):  
Klaus-Jürgen Range ◽  
Wilhelm Hegenbart ◽  
Anton M. Heyns ◽  
Franz Rau ◽  
Ulrich Klement
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Single Crystals ◽  
High Pressures ◽  
Monoclinic Space Group ◽  
Potassium Ions ◽  
Synthesis And Crystal Structure ◽  
Space Group ◽  
High Pressure Synthesis ◽  
Pressure Synthesis

Potassium tungstate, K2WO4, decomposes at high pressures to give K2W2O7 and other products. Single crystals of K2W2O7 could be synthesized from a mixture of K2WO4 + WO3 at 40kbar, 1000 °C. The crystals are monoclinic, space group P21/c, with a = 3.883(1) A, b = 13.653(4) Å, c = 5.960(1) Å, β = 90.40(3)°, and Ζ = 2.The structure is comprise of distorted WO6-octahedra (W–O = 1.75-2.13 A) which are connected by corner- and edgesharing, thus forming layers with a sequence ABAB ... along [010]. The potassium ions are situated between the layers with K–O distances of 2.66-3.04 A.Rb2W2O7, synthesized from a Rb2WO4/WO3-mixture at 40 kbar, 1000 °C, is isostructural with K2W2O7 (a = 3.9645(4) Å, b = 14.119(1) Å, c = 6.0415(5) Å,β = 90.446(9)°.

Ein Orthoperrhenat mit flächenverknüpften ReO6-Oktaedern: Hochdrucksynthese und Kristallstruktur von K3NaRe2O9 / An Orthoperrhenate with Face-Sharing ReO6 Octahedra: High-Pressure Synthesis and Crystal Structure of K3NaRe2O9

1993 ◽  
Vol 48 (2) ◽  
pp. 237-239 ◽  
Author(s):  
Klaus-Jürgen Range ◽  
Alexandra Atzesdorfer
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Title Compound ◽  
Technical Grade ◽  
Synthesis And Crystal Structure ◽  
Space Group ◽  
High Pressure Synthesis ◽  
Pressure Synthesis ◽  
High Pressure Reaction ◽  
Type Apparatus

AbstractThe title compound was prepared by high-pressure reaction of rhenium metal with technical grade (i.e., Na containing) KO2 in a modified Belt-type apparatus (20 kbar, 1000 °C, 60 min, Au capsule). The amber-coloured crystals are very hygroscopic and decompose rapidly when exposed to air. K3NaRe2O9 crystallizes hexagonally, space group P63/mmc, with a = 6.012(1), c = 14.342(14) Å, c/a = 2.386 and Z = 2. The structure was refined to R = 0.031, Rw = 0.023 for 422 independent, absorption-corrected reflections with l > σ (I). K3NaRe2O9 is isostructural with 6H-BaTiO3, a perowskite variant, and contains Na and Re in octaedral coordination. Two ReO6 octahedra are face-sharing, thus creating a Re2O9 double octahedron with a Re-R e distance of 2.92 Å.

High-Pressure Synthesis and Crystal Structure of the New Orthorhombic Polymorph β-HgB4O7

2005 ◽  
Vol 60 (8) ◽  
pp. 815-820 ◽  
Author(s):  
Holger Emme ◽  
Matthias Weil ◽  
Hubert Huppertz
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Ambient Pressure ◽  
Normal Pressure ◽  
High Pressure Phase ◽  
Synthesis And Crystal Structure ◽  
Space Group ◽  
High Pressure Synthesis ◽  
Pressure Synthesis ◽  
Pressure Phase

The new orthorhombic polymorph β-HgB4O7 has been synthesized under high-pressure and hightemperature conditions in a Walker-type multianvil apparatus at 7.5 GPa and 600 °C. β-HgB4O7 is isotypic to the known ambient pressure phases MB4O7 (M = Sr, Pb, Eu) and the high-pressure phase β-CaB4O7 crystallizing with two formula units in the space group Pmn21 with lattice parameters a = 1065.6(2), b = 438.10(9), and c = 418.72(8) pm. The relation of the crystal structure of the high-pressure phase β-HgB4O7 to the normal pressure phase α-HgB4O7 as well as the relation to the isotypic phases MB4O7 (M = Sr, Pb, Eu) and β-CaB4O7 are discussed.

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

High-pressure synthesis and crystal structure of non-centrosymmetric K2Ca3(CO3)4

CrystEngComm ◽  
2021 ◽  
Author(s):  
Sergey V. Rashchenko ◽  
Anton Shatskiy ◽  
Mark Ignatov ◽  
Anton V. Arefiev ◽  
Konstantin Litasov
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Synthesis And Crystal Structure ◽  
High Pressure Synthesis ◽  
Pressure Synthesis

A new non-centrosymmetric K2Ca3(CO3)4 crystal (P212121, a = 7.39134(18) Å, b = 8.8153(2) Å, c = 16.4803(4) Å) was synthesized in multianvil press at a pressure of 3 GPa and...

High-pressure synthesis and crystal structure of the strontium tungstate Sr3W2O9

2018 ◽  
Vol 74 (2) ◽  
pp. 120-124 ◽  
Author(s):  
Daisuke Urushihara ◽  
Toru Asaka ◽  
Koichiro Fukuda ◽  
Hiroya Sakurai
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
High Pressure Phase ◽  
X Ray Diffraction ◽  
Rotation Symmetry ◽  
Synthesis And Crystal Structure ◽  
High Pressure Synthesis ◽  
Transmission Electron ◽  
Pressure Synthesis ◽  
Pressure Phase

The strontium tungstate compound Sr3W2O9 was prepared by a high-pressure synthesis technique. The crystal structure was determined by single-crystal X-ray diffraction and transmission electron microscopy. The structure was found to be a hettotype structure of the high-pressure phase of Ba3W2O9, which has corner-sharing octahedra with a trigonal symmetry. Sr3W2O9 has a monoclinic unit cell of C2/c symmetry. One characteristic of the structure is the breaking of the threefold rotation symmetry existing in the high-pressure phase of Ba3W2O9. The substitution of Sr at the Ba site results in a significant shortening of the interlayer distances of the [AO3] layers (A = Ba, Sr) and causes a distortion in the crystal structure. In Sr3W2O9, there is an off-centre displacement of W6+ ions in the WO6 octahedra. Such a displacement is also observed in the high-pressure phase of Ba3W2O9.

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