Structure of melt-quenched AgIn3Te5

2011 ◽  
Vol 26 (3) ◽  
pp. 248-255 ◽  
Author(s):  
C. Rangasami ◽  
P. Malar ◽  
T. Osipowicz ◽  
Mahaveer K. Jain ◽  
S. Kasiviswanathan
Keyword(s):  
Electron Diffraction ◽  
Structure Refinement ◽  
Chalcopyrite Structure ◽  
Pixe Analysis ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Structure Space ◽  
Selected Area Electron Diffraction ◽  
P Type

Polycrystalline AgIn3Te5 synthesized by melt-quench technique has been analyzed using proton induced X-ray emission (PIXE), X-ray diffraction (XRD), and selected area electron diffraction. PIXE analysis yielded the content of Ag, In, and Te, respectively, to be 9.76%, 31.18%, and 59.05% by weight. Structure refinement was carried out considering those space groups from I- and P-type tetragonal systems which possess 4 symmetry and preserve the anion sublattice arrangement of the chalcopyrite structure (space group: I42d) as well. The results showed that AgIn3Te5 synthesized by melt-quench method crystallizes with P-type tetragonal structure (space group: P42c; unit-cell parameters a = 6.2443(8) and c = 12.5058(4) Å), the presence of which was corroborated by selected area electron diffraction studies.

The solid solution TbNiIn1−x Ga x

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Myroslava Horiacha ◽  
Galyna Nychyporuk ◽  
Rainer Pöttgen ◽  
Vasyl Zaremba
Keyword(s):  
Solid Solution ◽  
Unit Cell ◽  
Type Structure ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Structure Space ◽  
Arc Melting

Abstract Phase formation in the solid solution TbNiIn1−x Ga x at 873 K was investigated in the full concentration range by means of powder X-ray diffraction and EDX analysis. The samples were synthesized by arc-melting of the pure metals with subsequent annealing at 873 K for one month. The influence of the substitution of indium by gallium on the type of structure and solubility was studied. The solubility ranges have been determined and changes of the unit cell parameters were calculated on the basis of powder X-ray diffraction data: TbNiIn1–0.4Ga0–0.6 (ZrNiAl-type structure, space group P 6 ‾ 2 m $P‾{6}2m$ , a = 0.74461(8)–0.72711(17) and c = 0.37976(5)–0.37469(8) nm); TbNiIn0.2–0Ga0.8–1.0 (TiNiSi-type structure, space group Pnma, а = 0.68950(11)–0.68830(12), b = 0.43053(9)–0.42974(6), с = 0.74186(10)–0.73486(13) nm). The crystal structures of TbNiGa (TiNiSi type, Pnma, a = 0.69140(5), b = 0.43047(7), c = 0.73553(8) nm, wR2=0.0414, 525 F 2 values, 21 variables), TbNiIn0.83(1)Ga0.17(1) (ZrNiAl type, P 6 ‾ 2 m $P‾{6}2m$ , a = 0.74043(6), c = 0.37789(3) nm, wR2 = 0.0293, 322 F 2 values, 16 variables) and TbNiIn0.12(2)Ga0.88(2) (TiNiSi type, Pnma, a = 0.69124(6), b = 0.43134(9), c = 0.74232(11) nm, wR2 = 0.0495, 516 F 2 values, 21 variables) have been determined. The characteristics of the solid solutions and the variations of the unit cell parameters are briefly discussed.

CeLi2As2, eine ternäre Verbindung im CaAl2Si2-Typ / CeLi2As2, a Ternary Compound in the CaAl2Si2-Type

1979 ◽  
Vol 34 (8) ◽  
pp. 1169-1170 ◽  
Author(s):  
Hans-Uwe Schuster ◽  
Herrad-Odilia Fischer
Keyword(s):  
Ternary Compound ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Structure Space

X-ray investigations on the ternary compound CeLi2As2 showed it to crystallize in the trigonal CaAl2Si-2-structure, space group P3̄m1-D33d- The cell parameters are: a = 431,1 pm, c = 698,4 pm, c/a = 1,62

scholarly journals Electron and X-ray diffraction – two worlds united

2014 ◽  
Vol 70 (a1) ◽  
pp. C926-C926
Author(s):  
Ute Kolb ◽  
Yasar Krysiak ◽  
Tatiana Gorelik ◽  
Enrico Mugnaioli
Keyword(s):  
Electron Diffraction ◽  
Structure Refinement ◽  
Amorphous State ◽  
Two Dimensions ◽  
Sufficient Information ◽  
X Ray ◽  
Cell Parameters ◽  
Extra Information ◽  
Structure Solution ◽  
Diffraction Patterns

Small crystals structure solution usually done with X-ray powder diffraction (XRPD) provides bulk information and is powerful for in-situ investigations. Peak overlap in the one-dimensional data causes problems e.g. for polyphasic or impure samples and large cell parameters thus peak indexing and intensity extraction are the main issues where x-ray powder data may be supported by extra information. Electrons sample smaller volumes but strong coulombic interaction cause multiple scattering effects changing intensities often so strong that a structure solution is becoming impossible. Nevertheless, oriented electron diffraction patterns may provide sufficient information to support indexing or the assignment of impurity peaks in the case of low quality x-ray powder pattern. Reciprocal space tomography [1] uses a series of non-oriented diffraction patterns for which dynamical effects are significantly reduced and an enhanced amount of independent reflections sampled allows "ab-initio" crystal structure solution using established X-ray structure solution packages. Although structure refinement based on kinematical intensities is stable, achievable R values of 10-30% are high and final refinement may be performed based on X-ray powder data. Scanning transmission electron microscopy (STEM) for crystal tracking and nano electron diffraction (NED) is suitable for beam sensitive material, agglomerated particles, twins or intergrown phases on crystals down to 30nm size [2, 3]. Interesting properties of nanocrystalline materials are driven mainly by twinning, defects, disorder in one or two dimensions down to the amorphous state. Here low data completeness or uncertain intensity determination causes problems in structure solution. Here a mean structure may be determinable serving as a basis for disorder description and being used as a starting model being refined onto X-ray powder data maybe supported by a combination of the diffraction methods or by adding extra information.

Synthesis and Crystal Structures of ATi[Nb6Cl18] Compounds (A = K, Rb, Cs, In, Tl)

2000 ◽  
Vol 55 (2) ◽  
pp. 139-144 ◽  
Author(s):  
A. Nägele ◽  
E. Anokhina ◽  
J. Sitar ◽  
H.-J. Meyer ◽  
A. Lachgar
Keyword(s):  
Structure Refinement ◽  
Lattice Parameters ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Coordination Environment ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Crystal System ◽  
Rhombohedral Crystal

Abstract New quaternary niobium cluster chlorides corresponding to the general formula ATi[Nb6Cl18] (A = K, Rb, Cs, In, Tl) have been synthesized in sealed quartz tubes at 720 °C, starting from stoichiometric amounts of NbCl5, niobium metal, TiCl3, and ACl (A = K, Rb, Cs), or In or Tl metals. The structures of RbTi[Nb6Cl18] and CsTi[Nb6Cl18] were determined using single­ crystal X-ray diffraction. RbTi[Nb6Cl18] crystallizes in the rhombohedral crystal system, space group R3̄ (no. 148), Z = 3, with lattice parameters: a = 9.163(4), c = 25.014(14) Å (hexagonal setting). The structure refinement converged to R1 = 0.044 and wR2 = 0.058 for all data. In this structure, discrete [Nb6Cl18]4-cluster units are linked by Rb+ and Ti3+ cations, located in a 12-coordinated anticubeoctahedral and octahedral chloride coordination environment, respectively. In contrast, CsTi[Nb6Cl18] crystallizes in the trigonal crystal system, space group P3̄1c (no. 163), Z = 2. The lattice parameters were determined to be a = 9.1075(6), c = 17.0017(8) Å. The structure refinement gives the reliability factors R1 = 0.029 and wR2 = 0.063 for all data. The structure is built up of discrete octahedral [Nb6Cl18]4- cluster units, linked by Cs+ and Ti3+ cations which are located in a distorted hexagonal antiprismatic and octahedral chloride coordination environment, respectively. The structures of the compounds ATi[Nb6Cl18] (A = K, In, Tl) were found to be isotypic with RbTi[Nb6Cl18], and their unit cell parameters were refined using X-ray powder diffraction analysis.

Darstellung und Struktur der Verbindungen PrLi2P2, PrLi2As2 und NdLi2As2 / Preparation and Crystal Structure of PrLi2P2, PrLi2As2 and NdLi2As2

1980 ◽  
Vol 35 (10) ◽  
pp. 1322-1323 ◽  
Author(s):  
Herrad-Odilia Fischer ◽  
Hans-Uwe Schuster
Keyword(s):  
Crystal Structure ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Ternary Compounds ◽  
Structure Space ◽  
Ray Methods

Abstract Three ternary compounds PrLi2P2, PrLi2As2 and NdLi2As2 have been prepared and investigated by X-ray methods. They are isotypic and crystallize trigonally in the CaAl2Si2-structure (Space group P3̅m1-D3d3) with the follow-ing cell parameters:PrLi2P2: a = 419.6 pm, c = 682.1 pm;PrLi2As2: a = 429.9 pm, c = 696.0 pm;NdLi2As2: a = 428.7 pm, c = 692.2 pm.

X-ray study of CuGa x In1−x Se2 solid solutions

1989 ◽  
Vol 22 (6) ◽  
pp. 578-583 ◽  
Author(s):  
D. K. Suri ◽  
K. C. Nagpal ◽  
G. K. Chadha
Keyword(s):  
Solid Solution ◽  
Binary System ◽  
Crystallite Size ◽  
Solid Solutions ◽  
Lattice Parameters ◽  
Chalcopyrite Structure ◽  
Space Group ◽  
X Ray ◽  
Structure Space ◽  
A Value

The semiconducting compound CuGa x In1 − x Se2 crystallizes in the chalcopyrite structure (space group I{\bar 4}2d, Z = 4). The X-ray powder data for x = 1, 0.75, 0.6, 0.5, 0.4, 0.25 and 0.0 have been collected and it is found that the lattice parameters a and c and their ratio c/a vary linearly with x. Thus the composition of any chalcopyrite in the pseudo-binary system CuGaSe2 and CuInSe2 can be obtained from the accurate lattice parameters. The crystallite size determined from the (112) plane is minimum for x = 0.50 (~ 1000 Å) and away from x = 0.50 it increases. A value of u = 0.240 (5) has been established for fixing the Se-atom positions in the CuGa0.5In0.5Se2 solid solution. The JCPDS Diffraction File No. for CuInSe2 is 40-1487 and for CuGa0.5In0.5Se2 is 40-1488.

scholarly journals Synthesis, Structural Study and Thermal Expansion of Cesium Dititanium Tris(Phosphate)

2010 ◽  
Vol 12 (3,4) ◽  
pp. 189 ◽  
Author(s):  
E.A. Asabina ◽  
V.I. Pet'kov
Keyword(s):  
Thermal Expansion ◽  
Structure Refinement ◽  
Rietveld Analysis ◽  
Framework Structure ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Trigonal System ◽  
Cubic System

<p>The new phosphate CsTi<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub> was synthesized by precipitating method and characterized by scanning electron microscopy with energy-dispersive X-ray microanalyzer, X-ray powder diffraction and IR-spectroscopy. The structure refinement of the phosphate was carried out by a Rietveld analysis. CsTi<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub> crystallizes with the cubic system (space group <em>Ia</em><em>3</em><em>d</em>), its unit-cell parameters: <em>a</em> = 19.909(5) Å, <em>V</em> = 7892(1) Å<sup>3</sup>. It has the framework structure formed by TiO<sub>6</sub> octahedra and PO<sub>4</sub> tetrahedra, the two type positions of Cs<sup>+</sup> cations are in the cavities of the structure. CsTi<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub> structure features are discussed. The results of the undertaken study showed that cesium dititanium tris(phosphate) crystal structure differs from its isoformulic analogues CsZr<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub> and AM<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub> (A = Na, K, Rb; M = Ti, Zr), crystallizing in the trigonal system (space group <em>R</em> <em>c</em>) with the kosnarite type. Thermal expansion of the CsTi<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub> was studied: α<em><sub>a</sub></em> = 7.85∙10<sup>-6</sup> °C<sup>-1</sup>, α<em><sub>V</sub></em> = 23.5∙10<sup>-6</sup> °C<sup>-1 </sup>in the range 25–800 °C.</p>

Crystallographic data for BaMnSiO4: A new phase in the system BaO-MnO-SiO2

1997 ◽  
Vol 12 (3) ◽  
pp. 167-170
Author(s):  
D. D. Nihtianova ◽  
I. T. Ivanov ◽  
J. J. Macicek ◽  
I. K. Georgieva
Keyword(s):  
Electron Diffraction ◽  
Powder Diffraction ◽  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Lattice Parameters ◽  
Crystallographic Data ◽  
Space Group ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
New Phase

A new phase in the system BaO-MnO-SiO2 obtained by a pyrosynthetic method has been investigated using selected area electron diffraction (SAED), electron probe microanalysis (EPMA), and X-ray powder diffraction. The lattice parameters and a possible space group of the phase with a general composition BaMnSiO4 were determined as follows: a=5.370(2), b=18.447(7), c=8.498(5) Å, Z=8, Space Group Pmc21.

scholarly journals Stoichiometric partially-protonated states in hydroxide perovskites: the jeanbandyite enigma revisited

2017 ◽  
Vol 81 (2) ◽  
pp. 297-303 ◽  
Author(s):  
Mark D. Welch ◽  
Anthony R. Kampf
Keyword(s):  
Structure Determination ◽  
Structure Refinement ◽  
Structural Data ◽  
Original Description ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Long Range Ordering

AbstractThe original description of the hydroxide perovskite jeanbandyite gives a formula (Fe1–x3+,□x)(Sn1–y,□y) (OH)6 (□= vacancy), which implies the possibility of stoichiometric vacancies at B and B' sites. The validity of this formula has been questioned subsequently. Furthermore, jeanbandyite has metrically a cubic unit cell, but it is optically uniaxial. It is clear that a structure determination is needed to clarify the nature of this enigmatic mineral. Previous studies could find no crystals of sufficient quality for structure determination using X-ray diffractometers available at the time. Crystals of jeanbandyite from Hingston Down, Cornwall, UK and the type locality Llallagua, Bolivia, have been found that are of a quality that allows structure refinement by single-crystal X-ray diffraction. Structural data for crystals from each locality are presented that clarify the nature of jeanbandyite and raise some interesting questions concerning the significance of partially deprotonated states in perovskite-type structures. The structures of both jeanbandyite crystals are cubic with space group Pn3 and unit-cell parameters a = 7.658(2) Å (Llallagua) and 7.6427(2) Å (Hingston). The octahedral tilt system is a+a+a+ and corresponds to that of the aristotype of BB'(OH)6 hydroxide double perovskites. Structure determination demonstrates that B is very Fe3+-rich and B' is filled by Sn, thereby requiring revision of the general jeanbandyite formula to Fex3+Fe(1–x)2+Sn(OH)(6–x)Oxfor 1≥ × > 0.5, with an ideal end-member formula Fe3+Sn(OH)5O. As such, jeanbandyite corresponds to oxidized natanite with partially deprotonated oxygen sites. This stoichiometry cannot be represented in space group Pn3̄ for the observed unit cell as it implies more than one non-equivalent oxygen atom. Consequently, it is inferred that there is no long-range ordering of deprotonated oxygen sites. It is, however, conceivable that the uniaxial optical character of jeanbandyite is linked to the local short-range order of deprotonated domains.

Bimolecular and Monomolecular Lipid Films: Selected Area Electron Diffraction

1969 ◽  
Vol 27 ◽  
pp. 338-339
Author(s):  
Robert M. Glaeser ◽  
David W. Deamer
Keyword(s):  
Electron Diffraction ◽  
Membrane Structure ◽  
Molecular Organization ◽  
Membrane Material ◽  
X Ray Diffraction ◽  
Membrane Systems ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Lipid Films ◽  
Ultimate Objective

In the investigation of the molecular organization of cell membranes it is often supposed that lipid molecules are arranged in a bimolecular film. X-ray diffraction data obtained in a direction perpendicular to the plane of suitably layered membrane systems have generally been interpreted in accord with such a model of the membrane structure. The present studies were begun in order to determine whether selected area electron diffraction would provide a tool of sufficient sensitivity to permit investigation of the degree of intermolecular order within lipid films. The ultimate objective would then be to apply the method to single fragments of cell membrane material in order to obtain data complementary to the transverse data obtainable by x-ray diffraction.

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