ChemInform Abstract: STRUCTURE REFINEMENT OF TITANIUM ANTIMONIDE(TI5SB3) FROM SINGLE CRYSTAL DATA

AbstractThe new compounds A4[Nb6Cl12(N3)6](H2O)2 (A = Rb, Cs) were synthesized from In4[Nb6Cl12Cl6] by substituting six terminal Cl ligands and the In+ ions in methanolic solution. An X-ray structure refinement was performed on single-crystal data of Rb4[Nb6Cl12(N3)6](H2O)2 (1) (space group P1̄, Z = 1, a = 912.5(1) pm, b = 937.2(1) pm, c = 1062.0(1) pm, α = 96.88(2)°, β = 101.89(1)°, γ = 101.44(2)°) and Cs4[Nb6Cl12(N3)6](H2O)2 (2) (space group PI, Z = 1, a = 920.9(5) pm, b = 947.9(7) pm, c = 1091.8(7) pm, α = 96.89(6)°, β = 103.35(5)°, γ = 101.60(5)°. Each of the centrosymmetric [Nb6Cl12(N3)6]4- ions of the isotypic compounds contains six terminal azide groups at the corners of the octahedral niobium cluster (d̄Nb-N = 226(1) pm (1), 225(1) pm (2), bond angles Nb-N-N 120-127°). The [Nb6Cl12(N3)6]4- ions are linked via Rb-N and Rb-Cl interactions of the Rb+ ions to form a three-dimensional structure. Crystals of the compounds react explosively on heating or mechanical pressure.

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Structure Refinement of Ti5Sb3 from Single-crystal Data.

Acta Chemica Scandinavica ◽

10.3891/acta.chem.scand.31a-0889 ◽

1977 ◽

Vol 31a ◽

pp. 889-890 ◽

Cited By ~ 13

Author(s):

Rolf Berger ◽

N. W. Larsen ◽

H. Svanholt ◽

Michel Pouchard ◽

Paul Hagenmuller ◽

...

Keyword(s):

Single Crystal ◽

Structure Refinement ◽

Crystal Data

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Single-crystal diffraction at the Extreme Conditions beamline P02.2: procedure for collecting and analyzing high-pressure single-crystal data

Journal of Synchrotron Radiation ◽

10.1107/s0909049513018621 ◽

2013 ◽

Vol 20 (5) ◽

pp. 711-720 ◽

Cited By ~ 42

Author(s):

André Rothkirch ◽

G. Diego Gatta ◽

Mathias Meyer ◽

Sébastien Merkel ◽

Marco Merlini ◽

...

Keyword(s):

High Pressure ◽

Single Crystal ◽

Structure Refinement ◽

Extreme Conditions ◽

Data Sets ◽

Crystal Data ◽

Area Detector ◽

Data Formats ◽

Commercial Software Package ◽

Data Collections

Fast detectors employed at third-generation synchrotrons have reduced collection times significantly and require the optimization of commercial as well as customized software packages for data reduction and analysis. In this paper a procedure to collect, process and analyze single-crystal data sets collected at high pressure at the Extreme Conditions beamline (P02.2) at PETRA III, DESY, is presented. A new data image format called `Esperanto' is introduced that is supported by the commercial software packageCrysAlisPro(Agilent Technologies UK Ltd). The new format acts as a vehicle to transform the most common area-detector data formatsviaa translator software. Such a conversion tool has been developed and converts tiff data collected on a Perkin Elmer detector, as well as data collected on a MAR345/555, to be imported into theCrysAlisProsoftware. In order to demonstrate the validity of the new approach, a complete structure refinement of boron-mullite (Al5BO9) collected at a pressure of 19.4 (2) GPa is presented. Details pertaining to the data collections and refinements of B-mullite are presented.

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Application of synchrotron through-the-substrate microdiffraction to crystals in polished thin sections

IUCrJ ◽

10.1107/s2052252515007794 ◽

2015 ◽

Vol 2 (4) ◽

pp. 452-463 ◽

Cited By ~ 8

Author(s):

Jordi Rius ◽

Oriol Vallcorba ◽

Carlos Frontera ◽

Inmaculada Peral ◽

Anna Crespi ◽

...

Keyword(s):

Single Crystal ◽

Materials Science ◽

Structure Refinement ◽

Reciprocal Lattice ◽

Direct Methods ◽

Crystal Data ◽

Oriented Crystal ◽

Data Set ◽

Thin Sections ◽

Patterson Function

The synchrotron through-the-substrate X-ray microdiffraction technique (tts-μXRD) is extended to the structural study of microvolumes of crystals embedded in polished thin sections of compact materials [Rius, Labrador, Crespi, Frontera, Vallcorba & Melgarejo (2011).J.Synchrotron Rad.18, 891–898]. The resulting tts-μXRD procedure includes some basic steps: (i) collection of a limited number of consecutive two-dimensional patterns (frames) for each randomly oriented crystal microvolume; (ii) refinement of the metric from the one-dimensional diffraction pattern which results from circularly averaging the sum of collected frames; (iii) determination of the reciprocal lattice orientation of each randomly oriented crystal microvolume which allows assigning thehklindices to the spots and, consequently, merging the intensities of the different frames into a single-crystal data set (frame merging); and (iv) merging of the individual crystal data sets (multicrystal merging) to produce an extended data set suitable for structure refinement/solution. Its viability for crystal structure solution by Patterson function direct methods (δ recycling) and for accurate single-crystal least-squares refinements is demonstrated with some representative examples from petrology in which different glass substrate thicknesses have been employed. The section of the crystal microvolume must be at least of the same order of magnitude as the focus of the beam (15 × 15 µm in the provided examples). Thanks to its versatility and experimental simplicity, this methodology should be useful for disciplines as disparate as petrology, materials science and cultural heritage.

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Analytical method for observed powder diffraction intensity data based on maximum likelihood estimation

Powder Diffraction ◽

10.1017/s0885715613000195 ◽

2013 ◽

Vol 28 (2) ◽

pp. 124-126 ◽

Cited By ~ 2

Author(s):

Takashi Ida ◽

Fujio Izumi

Keyword(s):

Maximum Likelihood ◽

Maximum Likelihood Estimation ◽

Single Crystal ◽

Powder Diffraction ◽

Rietveld Method ◽

Structure Refinement ◽

Likelihood Estimation ◽

New Method ◽

Structure Parameters ◽

Crystal Data

A new methodology based on maximum likelihood estimation for structure refinement using powder diffraction data is proposed. The method can not only optimize the parameters adjusted in Rietveld refinement but also parameters to specify errors in a model for statistical properties of the observed intensity. The results of structure refinements with relation to fluorapatite Ca5(PO4)3F, anglesite PbSO4, and barite BaSO4 are demonstrated. The structure parameters of fluorapatite and barite optimized by the new method are closer to single-crystal data than those optimized by the Rietveld method, while the structure parameters of anglesite, whose values optimized by the Rietveld method are already in good agreement with the single-crystal data, are almost unchanged by the application of the new method.

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The crystal structure of rabejacite, the Ca2+-dominant member of the zippeite group

Mineralogical Magazine ◽

10.1180/minmag.2014.078.5.11 ◽

2014 ◽

Vol 78 (5) ◽

pp. 1249-1264 ◽

Cited By ~ 7

Author(s):

J. Plášil ◽

M. Dušek ◽

J. Čejka ◽

J. Sejkora

Keyword(s):

Crystal Structure ◽

Single Crystal ◽

Crystal Chemistry ◽

Structure Refinement ◽

Structural Formula ◽

Crystal Data ◽

Triclinic Space Group ◽

X Ray ◽

Rich Variety ◽

Dominant Member

AbstractThe crystal structure of rabejacite from Jáchymov, ideally Ca2[(UO2)4O4(SO4)2](H2O)8, was solved by charge flipping from single-crystal data and refined to R1 = 11.94% for 1422 unique observed reflections [I > 3σ(I)]. According to single-crystal X-ray data, rabejacite is triclinic, space group P1̄ , with a = 8.7434(11), b = 8.309(3), c = 8.8693(10) Å , a = 77.86(2), b = 104.635(11), g = 82.935(18)°, V = 598.8(3) A˚ 3 and Z = 1, with Dcalc = 4.325 g cm–3. The structure refinement proved that rabejacite is related to the zippeite group of minerals, as it is based upon the structural sheets of the zippeite topology of composition [(UO2)4O4(SO4)2]4–. Located in the interlayer between the sheets, which are stacked perpendicular to [010], are Ca2+ cations and H2O groups. Ca2+ ions are [7]-coordinated, by three uranyl O atoms from adjacent sheets and four H2O groups. An additional H2O group, which is not bonded directly to any cation, is located in the interlayer. Along with rabejacite, its Cu-rich variety was found in the specimens examined and characterized structurally. Its crystal structure (R1 = 10.15% for 1049 reflections with I > 3s(I)) is practically the same as that of rabejacite, but there is an additional Cu2+ site located in between pairs of Ca polyhedra. The structural formula is (Ca1.56Cu0.40)Σ1.90[(UO2)4O4(SO4)2](H2O)8, Z = 1. Its existence suggests a greater diversity in zippeite crystal chemistry than was thought previously and also the possibility of a new Cu2+-dominant zippeite mineral besides pseudojohannite.

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Polymorphs of VO(PO3)2: synthesis and crystal structure refinement revisited

Zeitschrift für Kristallographie - Crystalline Materials ◽

10.1515/zkri-2020-0037 ◽

2020 ◽

Vol 235 (8-9) ◽

pp. 303-309

Author(s):

Sven Umlauf ◽

Markus Weber ◽

Robert Glaum

Keyword(s):

Crystal Structure ◽

Single Crystal ◽

Single Phase ◽

Structure Refinement ◽

Crystal Structure Refinement ◽

Crystal Data ◽

Synthesis And Crystal Structure ◽

X Ray ◽

Porcelain Crucible ◽

Silica Ampoule

AbstractThe monoclinic α-polymorph of (VIVO)(PO3)2 is obtained reproducibly by reaction of V2O5 and H3PO4 (85%) (Au crucible, 380 °C, 4 d). Its crystal structure was refined from X-ray single-crystal data [C2/c, Z = 4, a = 15.1038(7) Å, b = 4.193(2) Å, c = 9.573(9) Å, β = 126.45(3), R1 = 0.052, wR2 = 0.189 for 976 unique reflections with Fo > 4σ(Fo), 48 variables]. A single-phase powder of the β-polymorph is obtained by the reaction of V2O5, H3PO4 (85%) and oxalic acid, evaporating the mixture, and subsequent annealing (porcelain crucible, 800 °C in air, 2 d). Single crystals of β-(VIVO)(PO3)2 were grown in a sealed silica ampoule with chlorine as mineralizer. The crystal structure of the orthorhombic (pseudo-tetragonal) β-polymorph was refined from X-ray single-crystal data [pseudo-merohedral twin, Fdd2, Z = 8, a = 15.536(2) Å, b = 15.586(2) Å, c = 4.2611(5) Å, R1 = 0.032, wR2 = 0.068 for 1072 unique reflections with Fo > 4σ(Fo), 50 variables]. Earlier reports on a tetragonal polymorph with unusual geometric structure of the [(V≡O)O5] polyhedron are corrected.

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