Search results for "precession electron diffraction"

showing 4 items of 14 documents

Charoite, as an example of a structure with natural nanotubes

2012

Charoite from the Murun massif in Yakutiya, Russia (Vorob’ev 2008) was investigated using automated electron diffraction tomography (ADT) (Kolb et al. 2007, 2008; Mugnaioli et al. 2010) and precession electron diffraction (PED) (Mugnaioli et al. 2010, 2009), which allowed to determine the structure of charoite for the first time. The structure was solved ab initio in space group P21/m by direct methods using a fully kinematic approach. The least squares refinements with 2878 reflections F(hkl) >4s F converged to unweighted/weighted residuals R 1/wR 2 • 0.173/0.21 (Rozhdestvenskaya et al. 2010).

PhysicsBoron Nitride; Mirror Plane; Potassium Atom; Apical Oxygen; Kinematic ApproachApical OxygenAnalytical chemistryStructure (category theory)Ab initioengineering.materialLeast squaresPotassium AtomElectron diffractionCharoiteDirect methodsengineeringPrecession electron diffractionBoron NitrideKinematic ApproachBoron Nitride Mirror Plane Potassium Atom Apical Oxygen Kinematic ApproachMirror planeMirror Plane
researchProduct

A new hydrous Al-bearing pyroxene as a water carrier in subduction zones

2011

Abstract A new Hydrous Al-bearing PYroxene (HAPY) phase has been synthesized at 5.4 GPa, 720 °C in the MgO–Al2O3–SiO2–H2O model system. It has the composition Mg2.1Al0.9(OH)2Al0.9Si1.1O6, a C-centered monoclinic cell with a = 9.8827(2), b = 11.6254(2) c = 5.0828(1) A and β = 111.07(1)°. The calculated density is 3.175 g/cm3 and the water content is 6.9% H2O by weight. Its structure has been solved in space group C2/c by the recently developed automated electron diffraction tomography method and refined by synchrotron X-ray powder diffraction. HAPY is a single chain inosilicate very similar to pyroxenes but with three instead of two cations in the octahedral layer, bonded to four oxygens and…

PyroxenePrecession electron diffractionSubductionSilicatechemistry.chemical_compoundCrystallographyHydrous pyroxeneGeophysicschemistryElectron diffractionOctahedronSpace and Planetary ScienceGeochemistry and PetrologyEarth and Planetary Sciences (miscellaneous)Precession electron diffractionElectron diffraction tomography; Hydrous pyroxene; Precession electron diffraction; SubductionElectron diffraction tomographyChloriteGeologyPowder diffractionMonoclinic crystal systemEarth and Planetary Science Letters
researchProduct

Electron Diffraction Reinvestigation of CdCr<sub>2</sub>Se<sub>4</sub> and ZnCr<sub>2-x</sub>V<sub>x</su…

2013

Crystal structure of two spinel single crystals CdCr2Se4 and ZnCr2-xVxSe4 have been reinvestigated using automated electron diffraction tomography method with beam precession. 3D reciprocal space have been reconstructed base on recorded tilt series. For both samples crystal structure was refined and the cubic symmetry with space group Fd-3m was confirmed. No additional electron potential has been located beside occupied atom sites.

Reflection high-energy electron diffractionMaterials scienceGas electron diffractionSpinelCrystal structureengineering.materialCondensed Matter PhysicsAtomic and Molecular Physics and OpticsCrystallographyElectron diffractionengineeringPrecession electron diffractionGeneral Materials SciencePowder diffractionElectron backscatter diffractionSolid State Phenomena
researchProduct

Structural insights into M2O-Al2O3-WO3 (M = Na, K) system by electron diffraction tomography.

2015

TheM2O–Al2O3–WO3(M= alkaline metals) system has attracted the attention of the scientific community because some of its members showed potential applications as single crystalline media for tunable solid-state lasers. These materials behave as promising laser host materials due to their high and continuous transparency in the wide range of the near-IR region. A systematic investigation of these phases is nonetheless hampered because it is impossible to produce large crystals and only in a few cases a pure synthetic product can be achieved. Despite substantial advances in X-ray powder diffraction methods, structure investigation on nanoscale is still challenging, especially when the sample i…

electron crystallography; electron difffraction tomography; laser media; structure determination; tungstateElectron crystallographyChemistryMetals and AlloysAb initioAnalytical chemistryelectron difffraction tomographylaser mediaAtomic and Molecular Physics and OpticsNanocrystalline materialstructure determinationElectronic Optical and Magnetic MaterialsDiffraction tomographyelectron crystallographyElectron diffractionChemical physicstungstateMaterials ChemistryPrecession electron diffractionCrystallitePowder diffractionActa crystallographica Section B, Structural science, crystal engineering and materials
researchProduct