High-pressure synthesis and crystal structure analysis of PbTeO, a UV transparent material.

Using the additional parameter pressure (Walker-type multianvil device), the lead(II) oxidotellurate(VI) PbTeO was synthesized at conditions of 8 GPa and 750 °C, and for the first time its crystal structure was determined using single-crystal X-ray diffraction data. PbTeO crystallizes with four formula units in the monoclinic space group 2/ with unit cell parameters = 5.4142(4), = 4.

A Comparative Study of a High-Pressure Polymorph of IO and its Ambient-Pressure Modification.

A hitherto unknown modification of IO was obtained from high-pressure/high-temperature syntheses in a Walker-type multianvil device at 8 GPa and 250 °C. HP-IO crystallizes in the monoclinic crystal system with space group P2/c (no. 14) with the unit cell parameters a=12.

Polymorphism and polymorph-dependent luminescence properties of the first lithium oxonitridolithosilicate LiSiNO:Eu.

Building on studies of monoclinic LiSiNO, a polymorph, β-LiSiNO, with a previously unknown structure type was synthesized. The β-phase crystallizes in the orthorhombic space group (no. 61) with lattice parameters of = 18.

Theoretical and Al NMR Spectroscopic Investigations of Binary Intermetallic Alkaline-Earth Aluminides.

The binary alkaline-earth aluminides Al ( = Ca and Sr) and Al ( = Ca-Ba) have been synthesized from the elements and investigated via powder X-ray diffraction experiments. CaAl adopts the cubic MgCu-type structure (3̅), while SrAl crystallizes in the orthorhombic KHg-type (). LT-CaAl crystallizes with the monoclinic CaGa-type (2/), while HT-CaAl, SrAl, and BaAl adopt the tetragonal BaAl-type structure (4/).

First ternary tungsten tellurate(IV) WTeO with unique crystal structure type.

At multianvil high-pressure/high-temperature conditions of 10 GPa and 1273 K, the first ternary tungsten tellurate WTeO is formed, starting from a stoichiometric mixture of WO and TeO. The compound crystallizes triclinic in a hitherto unknown crystal structure type with the space group 1̄; (no. 2), and was refined from single-crystal X-ray diffractometer data: = 538.

The crystal structure and luminescence properties of the first lithium oxonitridolithosilicate LiSiNO:Eu.

The compound LiSiNO:Eu was synthesized in high temperature solid-state reactions in weld shut tantalum ampules and the crystal structure of LiSiNO has been determined by single-crystal X-ray diffraction. It crystallizes in the monoclinic space group 2/ (no. 15) with the lattice parameters = 1049.

Coexistence of Two Different Distorted Octahedral [MnF ] Sites in K [MnF ]: Manifestation in Spectroscopy and Magnetism.

As a consequence of the static Jahn-Teller effect of the E ground state of Mn in cubic structures with octahedral parent geometries, their octahedral coordination spheres become distorted. In the case of six fluorido ligands, [MnF ] anions with two longer and four shorter Mn-F bonds making elongated octahedra are usually observed. Herein, we report the synthesis of the compound K [MnF ] through a high-temperature approach and its crystallization by a high-pressure/high-temperature route.

La B O (OH): The First Acentric High-Pressure Borate Displaying Edge-Sharing BO Tetrahedra.

La B O (OH) was obtained by a high-pressure/high-temperature experiment at 6 GPa and 1673 K. The compound crystallizes in the space group P2 (no. 4) with the lattice parameters a=4.

Ferroelastic lattice rotation and band-gap engineering in quasi 2D layered-structure PdSe under uniaxial stress.

Transition metal dichalcogenides (TMDCs) have attracted extensive attention in recent years for their novel physical and chemical properties as well as promising applications in the future. In the present paper, based on first-principles simulations, we focused on the bulk of the TMDC material PdSe and provided new insights into its unique structural properties and electronic structures under uniaxial stress. For the first time, we revealed that this orthorhombic PdSe is an intrinsic ferroelastic material with stress-driven 90° lattice rotation in the layer stacking direction.

UF and the High-Pressure Polymorph HP-UF.

A laboratory-scale synthesis of UF is presented that utilizes the reduction of UF with sulfur in anhydrous hydrogen fluoride. An excess of sulfur can be removed by vacuum sublimation, yielding pure UF , as shown by powder X-ray diffraction, micro X-ray fluorescence analysis, infrared and Raman spectroscopy, as well as magnetic measurements. Furthermore, a single-crystalline, high-pressure modification of UF was obtained in a multi-anvil press at elevated temperatures.

LiCoTeO: synthesis, single-crystal structure and physical properties of a new tellurate compound with Co/Co mixed valence and orthogonally oriented Li-ion channels.

A tellurate compound with Co/Co mixed valence states and lithium ions within orthogonally oriented channels was realized in LiCoTeO. The single-crystal structure determination revealed two independent and interpenetrating Li/O and (Co,Te)/O substructures with octahedral oxygen coordination of the metal atoms. In contrast to other mixed oxides, a honeycomb-like ordering of CoO and TeO octahedra was not observed.

Verbeekite, the Long-Unknown Crystal Structure of Monoclinic PdSe.

Verbeekite, a monoclinic polymorph of PdSe, was reported for the first time in 2002 by Roberts et al. The mineral has been discovered in the Musonoi Cu-Co-Mn-U mine, Democratic Republic of Congo, and was named after Dr. Théodore Verbeek, the first geoscientist who studied the palladium mineralization there (1955-1967).

A ZrNiAl related high-pressure modification of CeRuSn.

Monoclinic CeRuSn with its own structure type transforms to a high-pressure modification at 11.5 GPa and 1470 K (1000 t press, Walker type module). The structure of the high-pressure phase was refined from X-ray single crystal diffractometer data at room temperature.

Synthesis and characterization of the new strontium borogermanate Sr(3-x/2)B(2-x)Ge(4+x)O₁₄ (x = 0.32).

The strontium borogermanate Sr(3-x/2)B(2-x)Ge(4+x)O14 (x = 0.32) was synthesized by high-temperature solid-state reaction of SrO, GeO2, and H3BO3 in a NaF/KF flux system using platinum crucibles. The structure determination revealed that Sr(3-x/2)B(2-x)Ge(4+x)O14 (x = 0.

Oxonium ions substituting cesium ions in the structure of the new high-pressure borate HP-Cs(1-x)(H(3)O)(x)B(3)O(5) (x=0.5-0.7).

The new high-pressure borate HP-Cs1-x (H3 O)x B3 O5 (x=0.5-0.7) was synthesized under high-pressure/high-temperature conditions of 6 GPa/900 °C in a Walker-type multianvil apparatus.

High-pressure synthesis and characterization of new actinide borates, AnB4O8 (An=Th, U).

New actinide borates ThB4O8 and UB4O8 were synthesized under high-pressure, high-temperature conditions (5.5 GPa/1100 °C for thorium borate, 10.5 GPa/1100 °C for the isotypic uranium borate) in a Walker-type multianvil apparatus from their corresponding actinide oxide and boron oxide.

Ce4Ag3Ge4O(0.5)--chains of oxygen-centered [OCe2Ce(2/2)] tetrahedra embedded in a [CeAg3Ge4] intermetallic matrix.

The oxidation of an intermetallic phase under high-pressure/high-temperature conditions led to the synthesis of Ce4Ag3Ge4O(0.5) exhibiting [OCe2Ce(2/2] tetrahedral chains, in which the oxygen atoms statistically occupy the tetrahedral centres. Starting from a 1:1:1 CeAgGe precursor (NdPtSb type), a multianvil high-pressure/high-temperature experiment at 11.

Effects of gigapascal level pressure on protein structure and function.

Information on very high pressure (VHP) effects on proteins is limited and therefore effects of VHP on chemistry, structure and function of two model proteins in medical use were studied. VHP (8 GPa) application to l-asparaginase (L-ASNase) resulted in faster mobility on clear native gels. VHP induced generation of lower-MW forms of L-ASNase but VHP treatment did not deteriorate asparaginase activity.

Crystal structures, phase-transition, and photoluminescence of rare earth carbodiimides.

Rare earth carbodiimides with the general formula RE 2(CN 2) 3 crystallize with two modifications. A monoclinic( C2/m) modification is obtained for RE = Y, Ce-Tm and a rhombohedral ( R3 c) modification for RE = Tm-Lu. The space group R3 c is confirmed by single-crystal structure determination on Lu 2(CN 2) 3 and indexed powder patterns of RE = Tm, Yb and Lu.

Microstrain sensitivity of orbital and electronic phase separation in SrCrO3.

An orbital ordering transition and electronic phase coexistence have been discovered in SrCrO3. This cubic, orbitally-degenerate perovskite transforms to a tetragonal phase with partial orbital order. The tetragonal phase is antiferromagnetic below 35-40 K, whereas the cubic phase remains paramagnetic at low temperatures.

An organometallic chimie douce approach to new Re(x)W(1-x)O3 phases.

Re(x)W(1-x)O3.H2O and Re(x)W(1-x)O3 phases are prepared by a new organometallic chimie douce concept employing the organometallic precursor methyltrioxorhenium.