Structure refinement of (Al, Zn)49Mg32-type phases by single-crystal X-ray diffraction

2000 ◽  
Vol 294-296 ◽  
pp. 327-330 ◽  
Author(s):  
W. Sun ◽  
F.J. Lincoln ◽  
K. Sugiyama ◽  
K. Hiraga
Keyword(s):  
Single Crystal ◽  
Structure Refinement ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Redetermination of Sr2PdO3 from single-crystal X-ray data

2019 ◽  
Vol 75 (1) ◽  
pp. 30-32
Author(s):  
Gohil S. Thakur ◽  
Hans Reuter ◽  
Claudia Felser ◽  
Martin Jansen
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Diffraction Data ◽  
Structure Refinement ◽  
Structure Type ◽  
X Ray Diffraction ◽  
High Quality ◽  
X Ray ◽  
Cell Parameters ◽  
Anisotropic Displacement Parameters

The crystal structure redetermination of Sr2PdO3 (distrontium palladium trioxide) was carried out using high-quality single-crystal X-ray data. The Sr2PdO3 structure has been described previously in at least three reports [Wasel-Nielen & Hoppe (1970). Z. Anorg. Allg. Chem. 375, 209–213; Muller & Roy (1971). Adv. Chem. Ser. 98, 28–38; Nagata et al. (2002). J. Alloys Compd. 346, 50–56], all based on powder X-ray diffraction data. The current structure refinement of Sr2PdO3, as compared to previous powder data refinements, leads to more precise cell parameters and fractional coordinates, together with anisotropic displacement parameters for all sites. The compound is confirmed to have the orthorhombic Sr2CuO3 structure type (space group Immm) as reported previously. The structure consists of infinite chains of corner-sharing PdO4 plaquettes interspersed by SrII atoms. A brief comparison of Sr2PdO3 with the related K2NiF4 structure type is given.

Structure Refinement of CePtSi and Hydrogenation Behavior of CePdGe, CePtSi and CePtGe

2007 ◽  
Vol 62 (4) ◽  
pp. 613-616 ◽  
Author(s):  
Wilfried Hermes ◽  
Ute Ch. Rodewald ◽  
Bernard Chevalier ◽  
Rainer Pötgena
Keyword(s):  
Single Crystal ◽  
Diffraction Data ◽  
Structure Refinement ◽  
Three Dimensional ◽  
Subsequent Annealing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydride Formation ◽  
Arc Melting ◽  
Cerium Compounds

The intermetallic cerium compounds CePdGe, CePtSi, and CePtGe were synthesized from the elements by arc-melting and subsequent annealing. The structure of CePtSi was refined from single crystal X-ray diffraction data: LaPtSi-type (ordered α-ThSi2 version), 141md, a = 419.6(1) and c = 1450.0(5) pm, wR2 = 0.0490, 362 F2 values and 16 variables. The Pt-Si distances within the three-dimensional [PtSi] network are 242 pm, indicating strong Pt-Si interactions. Hydrogenation of the three compounds at 623 K and 4 MPa H2 gave no indication for hydride formation.

A single-crystal neutron and X-ray diffraction study of a Li, Be-bearing brittle mica

2014 ◽  
Vol 78 (1) ◽  
pp. 55-72 ◽  
Author(s):  
G. D. Gatta ◽  
G. Nénert ◽  
G. Guastella ◽  
P. Lotti ◽  
A. Guastoni ◽  
...  
Keyword(s):  
Chemical Analysis ◽  
Single Crystal ◽  
Scattering Length ◽  
Structure Refinement ◽  
Site Occupancy ◽  
Emission Spectrometry ◽  
X Ray Diffraction ◽  
Plasma Atomic Emission Spectrometry ◽  
X Ray ◽  
Final Population

AbstractThe crystal chemistry of a meso-octahedral Li,Be-bearing mica from the Harding pegmatite (Dixon, Taos County, New Mexico, USA) has been investigated by constant-wavelength single-crystal neutron diffraction at 20 K, single-crystal X-ray diffraction at 100 K and inductively coupled plasma-atomic emission spectrometry (ICP-AES). The chemical composition based on ICP-AES analysis leads to the following chemical formula (calculated on the basis of 12 oxygen atoms):Ca(Na0.26K0.04Ca0.69)∑0.99M(Li0.29Mg0.03Fe0.023+Al1.78)∑2.12T(Al1.73Be0.16Si2.11)S4.00O12H2.53. The apparent excess of H is probably due to the fact that the fraction of H2O was assumed by difference to 100 wt.%, and slightly overestimated. On the basis of the previous experimental findings on Li,Be-bearing mica, X-ray (at 100 K) and neutron (at 20 K) structure refinements were performed in the space groupsCcandC2/c. The neutron structure refinement in the space groupCcoffers a view about the (Al,Be,Si)-tetrahedral ordering: the best fit of the refinement was reached with theT1 andT4 sites occupied by (Be + Al) andT2 andT3 fully occupied by Si. This leads to a final population ofT(Al1.88Be0.12Si2.00)∑4.00p.f.u., in reasonable agreement with the chemical analysis. The neutron refinement provides unambigous evidence of the occurrence of Li at theM1 site. The refined fraction of Li at theM1 site ranges between 0.27 and 0.29 a.p.f.u., in excellent agreement with the chemical analysis. The presence of Li, at least at a significant level, at theM2 (andM3) site can be ruled out, as a full site occupancy with the scattering length of Al was obtained. The location of the H sites and the complex hydrogen-bonding scheme are described. A comparison between the structure features of this Li,Be-mica and other brittle micas is carried out.

Single-Crystal Synthesis and Structure Refinement of Na0.44MnO2

2011 ◽  
Vol 170 ◽  
pp. 198-202 ◽  
Author(s):  
Junji Akimoto ◽  
Hiroshi Hayakawa ◽  
Norihito Kijima ◽  
Junji Awaka ◽  
Fuji Funabiki
Keyword(s):  
Single Crystal ◽  
Structure Refinement ◽  
Bond Distance ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Single Chain ◽  
X Ray ◽  
Crystal Synthesis ◽  
Manganese Valence ◽  
First Time

Single crystals of Na0.44MnO2 (=Na4Mn9O18) have been synthesized by a flux method at 1173 K for the first time. The crystal structure of Na0.44MnO2 has been refined by single-crystal X-ray diffraction method. The framework structure consists of double and triple rutile-type chains of edge-sharing MnO6 octahedra and a single chain of edge-sharing MnO5. The Mn-O bond distance and bond valence analyses revealed the manganese valence Mn3+/Mn4+ ordering in the Na0.44MnO2 structure.

scholarly journals Crystal structure and XANES investigation of petzite, Ag3AuTe2

2019 ◽  
Vol 75 (2) ◽  
pp. 273-278
Author(s):  
Hidetomo Hongu ◽  
Akira Yoshiasa ◽  
Massimo Nespolo ◽  
Tsubasa Tobase ◽  
Makoto Tokuda ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Crystal Structures ◽  
Chemical Bonding ◽  
Structure Refinement ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Absolute Structure ◽  
Golden Mile

Petzite, Ag3AuTe2, crystallizes in the space group I4132, which is a Sohncke type of space group where chiral crystal structures can occur. The structure refinement of petzite reported long ago [Frueh (1959). Am. Mineral. 44, 693–701] did not provide any information about the absolute structure. A new single-crystal X-ray diffraction refinement has now been performed on a sample from Lake View Mine, Golden Mile, Kalgoorlie, Australia, which has resulted in a reliable absolute structure [a Flack parameter of 0.05 (3)], although this corresponds to the opposite enantiomorph reported previously. The minimum Te–Te distance is 3.767 (3) Å, slightly shorter than the van der Waals bonding distance, which suggests a weak interaction between the two chalcogens. XANES spectra near the Au and Te L III edges suggest that the chemical-bonding character of Au in petzite is more metallic than in other gold minerals.

A Yb3+-doped NaY(WO4)2crystal grown by the Czochralski technique

2008 ◽  
Vol 41 (3) ◽  
pp. 584-591 ◽  
Author(s):  
Jiandong Fan ◽  
Huaijin Zhang ◽  
Wentao Yu ◽  
Haohai Yu ◽  
Jiyang Wang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Structure Refinement ◽  
Czochralski Method ◽  
Point Of View ◽  
X Ray Diffraction ◽  
X Ray ◽  
Growth Habits ◽  
The Relationship

A transparent Yb3+:NaY(WO4)2single crystal with dimensions of 30 mm (diameter) × 40 mm has been grown by the Czochralski method. The high crystalline quality of the as-grown Yb3+:NaY(WO4)2crystals was confirmed by high-resolution X-ray diffraction. The effective segregation coefficients of elemental Yb, Na, Y and W in Yb3+:NaY(WO4)2were measured using the X-ray fluorescence method. Powder and single-crystal X-ray diffraction data of NaYb0.05Y0.95(WO4)2are reported. The structure refinement shows that NaYb0.05Y0.95(WO4)2crystallizes in the tetragonal space groupI41/a, witha=b= 5.2039 (2),c= 11.2838 (9) Å, α = β = γ = 90°,V= 305.57 (3) Å3andZ= 2. A series of possible growth faces (hkl) were determined from the crystal lattice and symmetry according to the Bravais–Friedel Donnay–Harker theory, and the relationship among crystal structure, growth habits and crystal morphology is discussed. In addition, the thermal properties of the crystal, including the specific heat, thermal expansion, thermal diffusion and thermal conductivity, were carefully investigated. The anisotropy of the crystal thermal conductivities is explained from the point of view of the crystal structure.

scholarly journals Crystal structure refinement of MgSiO3high temperature C2/c clinoenstatite

2014 ◽  
Vol 70 (a1) ◽  
pp. C79-C79
Author(s):  
Akira Yoshiasa ◽  
Akihiko Nakatsuka ◽  
Maki Okube ◽  
Tomoo Katsura
Keyword(s):  
High Temperature ◽  
Single Crystal ◽  
Structure Refinement ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
Temperature Quenching ◽  
Single Crystal Diffraction ◽  
X Ray ◽  
Metastable Structure ◽  
Rapid Pressure

The high-temperature clinoenstatite (HT-CEn) is one of the important MgSiO3 pyroxene polymorph. The single-crystal of C2/c HT-CEn endmember is firstly synthesized by rapid pressure-temperature quenching from 15-16 GPa and 900-19000C [1]. No report that it is produced as single crystal or large domain has been made on the MgSiO3 endmember. The HT-CEn-type modifications are observed in Ca-poor Mg-Fe clinoenstatite and pigeonite and are always found to be unquenchable in rapid cooling. The high pressure and high temperature experiments of MgSiO3 composition were carried out with a Kawai-type multi-anvil apparatus. The samples were quenched by rapidly releasing the oil pressure load and/or by blow out of anvil cell gasket. The space group of C2/c is strictly determined by Rigaku RAPID Weissenberg photographs and synchrotron radiation. Single-crystal X-ray diffraction experiments were performed at ambient conditions using a Rigaku AFC-5 four circle diffractometer. A total of 9383 reflections was measured and averaged in Laue symmetry 2/m to give 766 independent reflections used for the structure refinements. Final reliability factors converged smoothly to R = 0.029. The single-crystal diffraction analysis shows that the unusual bonding distances frozen in this metastable structure. The degree of kinking of the silicate tetrahedral chains is 1750for HT-CEn. The chain angle for HP-CEn is substantially smaller (1350) and the angle for L-CEn turned to the opposite direction at -1600(=2000). The degree of kinking increases by being curved in more than 1800in the transition from HT-CEn to L-CEn. As for the reverse change from the expansion to the stretch, a potential barrier exists in the point of the continuity. It is suggested that the reason which can quench structure under ambient conditions is the present HT-CEn single crystal was formed by the isosymmetric phase transition from HP-CEn. HT-CEn type single-crystals cannot be frozen without pressure.

Structure Refinement of the S-Phase Precipitate MgCuAl2

2005 ◽  
Vol 60 (5) ◽  
pp. 491-494 ◽  
Author(s):  
Birgit Heying ◽  
Rolf-Dieter Hoffmann ◽  
Rainer Pöttgen
Keyword(s):  
Single Crystal ◽  
Original Work ◽  
Induction Furnace ◽  
Structure Refinement ◽  
S Phase ◽  
Crystal Chemical ◽  
X Ray Diffraction ◽  
Variable Parameters ◽  
X Ray ◽  
Phase Precipitate

The technologically important S-phase precipitate MgCuAl2 has been synthesized from the elements in a sealed tantalum tube in an induction furnace. The aluminide was investigated by powder and single crystal X-ray diffraction methods: Cmcm, a = 401.19(9), b = 926.5(2), c = 712.4(1) pm, wR2 = 0.0425, 234 F2 values, and 16 variable parameters. The new crystallographic data fully confirm the original work by Perlitz and Westgren [Ark. Kemi, Mineral. Geol. 16, 1 (1943)], but the present structure refinement has led to a much higher precision. The crystal chemical peculiarities of MgCuAl2 are briefly discussed.

Neue Strukturverfeinerung und Eigenschaften von Cr3C2/Structure Refinement and Properties of Cr3C2

2003 ◽  
Vol 58 (9) ◽  
pp. 929-933 ◽  
Author(s):  
Jochen Glaser ◽  
Ruth Schmitt ◽  
H.-Jürgen Meyer
Keyword(s):  
Crystal Structure ◽  
Electronic Structure ◽  
Single Crystal ◽  
Structure Refinement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Arc Melting ◽  
Metal Atoms ◽  
Extended Hückel Calculations ◽  
Trigonal Prismatic

Cr3C2 was obtained from arc-melting of pellets made of carbon and chromium. The structure of Cr3C2 was determined by single crystal X-ray diffraction (Pnma, Z = 4, a = 553.99(6), b = 283.27(4), c = 1149.4(1) pm, R1 = 0.019 and wR2 = 0.037 for all collected reflections). The crystal structure contains isolated carbon atoms which reside inside of trigonal prismatic voids of metal atoms. The compound exhibits temperature independent paramagnetism. The electronic structure of Cr3C2 has been investigated using extended Hückel calculations.

Crystal and Molecular Structure of mer-cis-(PEt2Ph)2(PPri3)H-trans-Cl2IrIII

1996 ◽  
Vol 49 (11) ◽  
pp. 1253 ◽  
Author(s):  
EJ Ditzel ◽  
KD Griffiths ◽  
GB Robertson
Keyword(s):  
Molecular Structure ◽  
Single Crystal ◽  
Diffraction Analysis ◽  
Crystal And Molecular Structure ◽  
Structure Refinement ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray ◽  
Metal Ligand

The structure of mer-cis-(PEt2Ph)2(PPri3)H-trans-Cl2IrIII (4) has been determined by single-crystal X-ray diffraction analysis. Crystals are monoclinic, space group P21/c, with a 11.607(1), b 21.553(1), c 14.066(1) Ǻ, β 109.04(1)? and Z 4. Structure refinement by full-matrix least-squares analysis (3244 unique reflections, 316 parameters) converged with R 0.034 and Rw 0.041. The PEt2Ph ligands are similarly disposed to their PMe2Ph counterparts in mer-cis-(PEt2Ph)2(PPri3)H-trans-Cl2IrIII (2) but the PPri3 ligands are differently oriented and differently configured. Metal-ligand distances [ Ir -P(1,2,3) 2.333(2), 2.404(2), 2.368(2) Ǻ; Ir-Cl (1,2) 2.388(2), 2.400(2) Ǻ] are all within c. 0.02 Ǻ of those in (2). The P-Ir -P(trans) angle is 155.3(1)°.

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