scholarly journals `Pd20Sn13' revisited: crystal structure of Pd6.69Sn4.31

2015 ◽  
Vol 71 (7) ◽  
pp. 807-809 ◽  
Author(s):  
Wilhelm Klein ◽  
Hanpeng Jin ◽  
Viktor Hlukhyy ◽  
Thomas F. Fässler
Keyword(s):  
Crystal Structure ◽  
Title Compound ◽  
Original Structure ◽  
Site Symmetry ◽  
Structure Model ◽  
Reaction Route ◽  
X Ray ◽  
Anisotropic Displacement Parameters ◽  
Solid State Reaction Route ◽  
Atomic Coordinates

The crystal structure of the title compound was previously reported with composition `Pd20Sn13' [Sarahet al.(1981).Z. Metallkd,72, 517–520]. For the original structure model, as determined from powder X-ray data, atomic coordinates from the isostructural compound Ni13Ga3Ge6were transferred. The present structure determination, resulting in a composition Pd6.69Sn4.31, is based on single crystal X-ray data and includes anisotropic displacement parameters for all atoms as well as standard uncertainties for the atomic coordinates, leading to higher precision and accuracy for the structure model. Single crystals of the title compound were obtainedviaa solid-state reaction route, starting from the elements. The crystal structure can be derived from the AlB2type of structure after removing one eighth of the atoms at the boron positions and shifting adjacent atoms in the same layer in the direction of the voids. One atomic site is partially occupied by both elements with a Pd:Sn ratio of 0.38 (3):0.62 (3). One Sn and three Pd atoms are located on special positions with site symmetry 2. (Wyckoff letter 3aand 3b).

scholarly journals Crystal Structure of the Arsenate(V) NaTi2[AsO4]3

2010 ◽  
Vol 65 (5) ◽  
pp. 639-642 ◽  
Author(s):  
Hamdi Ben Yahia ◽  
Ute Ch. Rodewald ◽  
Rainer Pöttgen
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Single Crystal ◽  
Solid State Reaction ◽  
Three Dimensional ◽  
Salt Flux ◽  
Reaction Route ◽  
X Ray ◽  
Anisotropic Displacement Parameters ◽  
Solid State Reaction Route

The arsenate(V) NaTi2[AsO4]3 has been synthesized by a solid-state reaction route using a salt flux. Its structure has been solved and refined from single-crystal X-ray data: NASICON- type, R3̄c, a = 8.8057(5), c = 22.2406(15) Å, Z = 6, wR(F2) = 0.0617 for 576 unique reflections and 30 variables. The NaTi2[AsO4]3 structure consists of a three-dimensional framework of corner-sharing AsO4 tetrahedra and TiO6 octahedra. The negatively charged [Ti2As3O12] framework gives rise to two different interstices. The Na+ cation is located on the 6b position with a trigonal antiprismatic coordination and enhanced anisotropic displacement parameters.

scholarly journals Redetermination of the crystal structure of RhPb2 from single-crystal X-ray diffraction data, revealing a rhodium deficiency

2021 ◽  
Vol 77 (12) ◽  
Author(s):  
Takashi Mochiku ◽  
Yoshitaka Matsushita ◽  
Nikola Subotić ◽  
Takanari Kashiwagi ◽  
Kazuo Kadowaki
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Diffraction Data ◽  
Structure Type ◽  
Site Symmetry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
Anisotropic Displacement Parameters ◽  
Slight Deficiency

RhPb2 (rhodium dilead) is a superconductor crystallizing in the CuAl2 structure type (space group I4/mcm). The Rh and Pb atoms are located at the 4a (site symmetry 422) and 8h (m.2m) sites, respectively. The crystal structure is composed of [RhPb8] antiprisms, which share their square faces along the c axis and the edges in the direction perpendicular to the c axis. We have succeeded in growing single crystals of RhPb2 and have re-determined the crystal structure on basis of single-crystal X-ray diffraction data. In comparison with the previous structure studies using powder X-ray diffraction data [Wallbaum (1943). Z. Metallkd. 35, 218–221; Havinga et al. (1972). J. Less-Common Met. 27, 169–186], the current structure analysis of RhPb2 leads to more precise unit-cell parameters and fractional coordinates, together with anisotropic displacement parameters for the two atoms. In addition and likewise different from the previous studies, we have found a slight deficiency of Rh in RhPb2, leading to a refined formula of Rh0.950 (9)Pb2.

Crystal Structure of the New Phosphate AgMnPO4

2009 ◽  
Vol 64 (7) ◽  
pp. 875-878 ◽  
Author(s):  
Hamdi Ben Yahia ◽  
Etienne Gaudin ◽  
Jacques Darriet
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Diffraction Data ◽  
X Ray Diffraction ◽  
Reaction Route ◽  
X Ray ◽  
Solid State Reaction Route ◽  
Symmetry Space ◽  
Symmetry Space Group ◽  
Silver Atoms

The new compound AgMnPO4 has been synthesized by a solid-state reaction route. Its crystal structure was determined from single-crystal X-ray diffraction data. AgMnPO4 crystallizes with triclinic symmetry, space group P1̄, a = 9.6710(6), b = 5.695(2), c = 6.629(3) Å , α = 102.55(3), β = 105.85(2), γ = 80.70(2)◦, and Z = 4. Its structure is built up from MnO6, MnO5 and PO4 polyhedra forming tunnels filled with silver atoms.

scholarly journals Diterbium heptanickel: a crystal structure redetermination

2014 ◽  
Vol 70 (8) ◽  
pp. i42-i42
Author(s):  
Volodymyr Levytskyy ◽  
Volodymyr Babizhetskyy ◽  
Bohdan Kotur ◽  
Volodymyr Smetana
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
Title Compound ◽  
Stoichiometric Composition ◽  
Structure Type ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
Coordination Polyhedra ◽  
X Ray ◽  
Anisotropic Displacement Parameters

The crystal structure of the title compound, Tb2Ni7, was redetermined from single-crystal X-ray diffraction data. In comparison with previous studies based on powder X-ray diffraction data [Lemaireet al.(1967).C. R. Acad. Sci. Ser. B,265, 1280–1282; Lemaire & Paccard (1969).Bull. Soc. Fr. Mineral. Cristallogr.92, 9–16; Buschow & van der Goot (1970).J. Less-Common Met.22, 419–428], the present redetermination affords refined coordinates and anisotropic displacement parameters for all atoms. A partial occupation for one Tb atom results in the non-stoichiometric composition Tb1.962 (4)Ni7. The title compound adopts the Ce2Ni7structure type and can also be derived from the CaCu5structure type as an intergrowth structure. The asymmetric unit contains two Tb sites (both site symmetries 3m.) and five Ni sites (.m.,mm2, 3m., 3m., -3m.). The two different coordination polyhedra of Tb are a Frank–Kasper polyhedron formed by four Tb and 12 Ni atoms and a pseudo Frank–Kasper polyhedron formed by two Tb and 18 Ni atoms. The four different coordination polyhedra of Ni are Frank–Kasper icosahedra formed by five Tb and seven Ni atoms, four Tb and eight Ni atoms, three Tb and nine Ni atoms, and six Tb and six Ni atoms, respectively.

scholarly journals Influence of Processing Conditions on Crystal Structure of Bi6Fe2Ti3O18 Ceramics

2016 ◽  
Vol 61 (2) ◽  
pp. 881-886 ◽  
Author(s):  
A. Lisińska-Czekaj ◽  
M. Lubina ◽  
D. Czekaj ◽  
M. Rerak ◽  
B. Garbarz-Glos ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ambient Air ◽  
Processing Conditions ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
Reaction Route ◽  
X Ray ◽  
Number Of Layers ◽  
Solid State Reaction Route ◽  
Diffraction Patterns

Abstract Aim of the present research was to apply a solid state reaction route to fabricate Aurivillius-type ceramics described with the formula Bi6Fe2Ti3O18 (BFTO) and reveal the influence of processing conditions on its crystal structure. Pressureless sintering in ambient air was employed and the sintering temperatures were 850 and 1080 °C. It was found that the fabricated BFTO ceramics were multiphase ones. They consisted of two Bim+1Fem-3Ti3O3m+3 phases, namely the phase with m=5 (i.e. the stoichiometric phase) and m=4 (i.e. the phase with a reduced number of layers in the slab). Detailed X-ray diffraction patterns analysis showed that both phases adopted the same orthorhombic structure described with Fmm2 (42) space group. The ratio of weight fractions of the constituent phases (m=5): (m=4) was ~30:70.

scholarly journals Redetermination of Mg2B25 based on single-crystal X-ray data

2012 ◽  
Vol 68 (6) ◽  
pp. i50-i50 ◽  
Author(s):  
Luca Bindi ◽  
Alessandro Figini Albisetti ◽  
Giovanni Giunchi ◽  
Luciana Malpezzi ◽  
Norberto Masciocchi
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Diffraction Data ◽  
Structural Model ◽  
Structure Type ◽  
Site Symmetry ◽  
Metal Boride ◽  
X Ray Diffraction ◽  
X Ray ◽  
Anisotropic Displacement Parameters

The crystal structure of Mg2B25, dimagnesium pentaeicosaboride, was reexamined from single-crystal X-ray diffraction data. The structural model previously reported on the basis of powder X-ray diffraction data [Giunchi et al. (2006). Solid State Sci. 8, 1202–1208] has been confirmed, although a much higher precision refinement was achieved, leading to much smaller standard uncertainties on bond lengths and refined occupancy factors. Moreover, all atoms were refined with anisotropic displacement parameters. Mg2B25 crystallizes in the β-boron structure type and is isostructural with other rhombohedral compounds of the boron-rich metal boride family. Magnesium atoms are found in interstitial sites on special positions (two with site symmetry .m, one with .2 and one with 3m), all with partial occupancies.

scholarly journals Rerefinement of the crystal structure of trichloridosulfonium(IV) hexachloridouranate(V), (SCl3)[UCl6]

IUCrData ◽  
2020 ◽  
Vol 5 (7) ◽  
Author(s):  
Holger Lars Deubner ◽  
Sergei I. Ivlev ◽  
Florian Kraus
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Single Crystals ◽  
Lattice Parameters ◽  
Structure Model ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ionic Compound ◽  
Distorted Octahedral ◽  
Atomic Coordinates

Single crystals of trichloridosulfonium(IV) hexachloridouranate(V) were obtained from the reaction of uranium(IV) chloride with an excess of disulfur dichloride and studied by single-crystal X-ray diffraction. In comparison with the structure model reported previously [Sawodny et al. (1983). Z. Anorg. Allg. Chem. 499, 81–88.], the lattice parameters and fractional atomic coordinates were determined to a much higher precision, leading overall to an improved structure model. The ionic compound contains trigonal–pyramidal (SCl3)+ cations and slightly distorted octahedral [UCl6]− anions. The structure was refined as an inversion twin with a twin ratio of 4.4:1.

Single Crystal Structure of the Divalent Europium Chloroapatite Eu5(PO4)3Cl

2009 ◽  
Vol 64 (5) ◽  
pp. 577-580 ◽  
Author(s):  
Hamdi Ben Yahia ◽  
Ute Ch. Rodewald ◽  
Rainer Pöttgen
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Chloride Ions ◽  
Salt Flux ◽  
Reaction Route ◽  
X Ray ◽  
Divalent Europium ◽  
Solid State Reaction Route ◽  
Apatite Type ◽  
The Eu

The chloroapatite Eu5(PO4)3Cl has been synthesized by a solid-state reaction route using a salt flux. Its structure has been solved and refined from single crystal X-ray data: apatite type, P63/m, a = 988.36(4), c = 720.32(3) pm, Z = 2, R(F) = 0.021 and wR(F2) = 0.063 for 748 unique reflections and 40 variables. The Eu5(PO4)3Cl structure contains isolated (PO4)3− tetrahedra and two crystallographically independent divalent europium sites. The Eu12+ ion at the 4 f position is located in a distorted tri-capped trigonal prism whereas the Eu22+ ion at the 6h position is located in a strongly distorted square anti-prism. The chloride ions have octahedral europium coordination (307 pm Eu-Cl).

Evidence of a centre of symmetry: redetermination of Ni2.60Te2 from single-crystal data

2007 ◽  
Vol 63 (11) ◽  
pp. i188-i188 ◽  
Author(s):  
L. D. Gulay ◽  
M. Daszkiewicz ◽  
A. Pietraszko
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Title Compound ◽  
Previous Investigation ◽  
Crystal Data ◽  
Interatomic Distances ◽  
Space Group ◽  
X Ray ◽  
The Subject ◽  
Atomic Coordinates

The crystal structure of the title compound, nickel telluride, with composition Ni2.60Te2, has been the subject of a previous investigation based on X-ray powder data, when a slightly different composition of Ni2.58Te2 was determined [Gulay & Olekseyuk (2004). J. Alloys Compd, 376, 131–138]. In contrast to the previous refinement in the space group Pmc21, the redetermination from single-crystal data reveals a centre of symmetry and the structure was refined in the space group Pnma with improved precision for the atomic coordinates and interatomic distances. The structure can be described as a c × a × (3a)1/2 distorted orthorhombic variant of the hexagonal Ni1.10Se0.16Te0.74 structure. All atoms are situated on mirror planes.

scholarly journals Redetermination of brackebuschite, Pb2Mn3+(VO4)2(OH)

2016 ◽  
Vol 72 (3) ◽  
pp. 293-296 ◽  
Author(s):  
Barbara Lafuente ◽  
Robert T. Downs
Keyword(s):  
Crystal Structure ◽  
Spectroscopic Data ◽  
Structure Refinement ◽  
Common Vertex ◽  
Site Symmetry ◽  
X Ray Diffraction ◽  
Special Position ◽  
X Ray ◽  
Raman Spectroscopic ◽  
Anisotropic Displacement Parameters

The crystal structure of brackebuschite, ideally Pb2Mn3+(VO4)2(OH) [dilead(II) manganese(III) vanadate(V) hydroxide], was redetermined based on single-crystal X-ray diffraction data of a natural sample from the type locality Sierra de Cordoba, Argentina. Improving on previous results, anisotropic displacement parameters for all non-H atoms were refined and the H atom located, obtaining a significant improvement of accuracy and an unambiguous hydrogen-bonding scheme. Brackebuschite belongs to the brackebuschite group of minerals with general formulaA2M(T1O4)(T2O4)(OH, H2O), withA= Pb2+, Ba, Ca, Sr;M= Cu2+, Zn, Fe2+, Fe3+, Mn3+, Al;T1 = As5+, P, V5+; andT2 = As5+, P, V5+, S6+. The crystal structure of brackebuschite is based on a cubic closest-packed array of O and Pb atoms with infinite chains of edge-sharing [Mn3+O6] octahedra located about inversion centres and decorated by two unique VO4tetrahedra (each located on a special position 2e, site symmetrym). One type of VO4tetrahedra is linked with the1∞[MnO4/2O2/1] chain by one common vertex, alternating with H atoms along the chain, while the other type of VO4tetrahedra link two adjacent octahedra by sharing two vertices with them and thereby participating in the formation of a three-membered Mn2V ring between the central atoms. The1∞[Mn3+(VO4)2OH] chains run parallel to [010] and are held together by two types of irregular [PbOx] polyhedra (x= 8, 11), both located on special position 2e(site symmetrym). The magnitude of the libration component of the O atoms of the1∞[Mn3+(VO4)2OH] chain increases linearly with the distance from the centerline of the chain, indicating a significant twisting to and fro of the chain along [010]. The hydroxy group bridges one Pb2+cation with two Mn3+cations and forms an almost linear hydrogen bond with a vanadate group of a neighbouring chain. The O...O distance of this interaction determined from the structure refinement agrees well with Raman spectroscopic data.

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