scholarly journals Diffraction Pattern Simulation of Crystal Structure towards the Ionic Radius Changes Via Vesta Program

2019 ◽  
Vol 1 (2) ◽  
pp. 132-139
Author(s):  
Ari Sulistyo Rini

The Simulations of X-ray diffraction patterns of MgO, BaO and ZnS ceramics were successfully performed by VESTA program, based on the crystal structures visualization. The aim of this research was to obtain the relationship between ionic radius to the diffraction pattern. The X-ray diffraction pattern was generated from visualization of the crystal structure. The crystal structure information was obtained from JCPDS data which contained lattice parameter, atomic coordinate and the space group. The X-ray diffraction pattern parameters which are taken into account in this research are diffraction angle of 2 Theta and Intensity. The results indicated that the peak position and intensity of the diffraction pattern are influenced by ionic radius of the cations. Structural transformation was also detected from this simulation.

2018 ◽  
Vol 15 (1) ◽  
pp. 46
Author(s):  
Sundami Restiana ◽  
Ari Sulistyo Rini

Visualization of crystal structures and simulation of X-ray diffraction patterns of perovskite ceramic was successfully performed by VESTA software programs. The purpose of this research is to obtain the relation of lattice parameter, and composition to the diffraction pattern. The software program produces crystal structure information and a representative X-ray diffraction pattern for the ceramic materials. The program needs several input parameters such as the coordinates of each constituent atom, lattice parameters, and space symmetry. The obtained output of the software program are in the form of diffraction pattern graph and crystal structure data which gives the description of the profile and type (phase) of ceramic material. The results showed that the peak position and intensity of the diffraction pattern are influenced by the arrangement of  the atoms within the unit cell. The addition of impurity atoms such as Sr on the Ba side in BaTiO3 causes the BaTiO3 structure changes from Orthorombic (a≠b≠c) to Tetragonal (a=b≠c) structure. Based on the simulation, it can be predicted that the critical concentration of the change of structure occur at Sr concentration about 0.4.


2013 ◽  
Vol 29 (1) ◽  
pp. 28-32 ◽  
Author(s):  
Ana Palčić ◽  
Ivan Halasz ◽  
Josip Bronić

The crystal structure of copper(ii) citrate monohydrate (C6H4O7Cu2·H2O) has been solved from a mixture powder diffraction pattern. Approach to indexing, structure solution and Rietveld refinement of multiphase diffraction patterns is discussed. Rietveld refinement is carried out employing free-atom refinement and rigid body refinement.


2013 ◽  
Vol 46 (1) ◽  
pp. 99-107 ◽  
Author(s):  
Alla Arakcheeva ◽  
Philip Pattison ◽  
Annette Bauer-Brandl ◽  
Henrik Birkedal ◽  
Gervais Chapuis

The H2 antagonist cimetidine forms many polymorphs, several of which have resisted structural analysis thus far. Using single-crystal X-ray measurements obtained from synchrotron radiation, the crystal structure of cimetidine form C has been solved. This layered structure crystallizes in space groupC2/cwith an unusually large lattice parameter,a= 82.904 Å. The thickness of each layerLis equal toa′ =a/6 = 13.82 Å, anda= 6a′ originates from a sixfoldLLLL′L′L′ sequence withLandL′ differing by 0.5b. This packing is reminiscent of polytypic stacking in metals. A (3 + 1)-dimensional superspace model is derived and used to explain and predict many polytypic modifications. This model is characterized by (i) the (3 + 1)-dimensional symmetry groupX2/c(α0γ)00, whereX= 0\textstyle{1 \over 2}0\textstyle{1 \over 2}; (ii) the lattice parametera′ and modulation vectorq= 1/n(a′*); (iii) the atomic positions of a single molecule of cimetidine form C; (iv) the primary variable, 1/n. The model reproduces the previously solved structure, the 6M polytype, and generates the related polytypesnM with lattice parameteranM =na′ forn= 1, 2, 3, 4 and 5. A comparison of powder X-ray diffraction patterns available for cimetidine form C with those simulated for thenM polytypes suggests that the powder samples published previously probably contain a mixture of various polytypes.


2021 ◽  
Vol 323 ◽  
pp. 152-158
Author(s):  
Shou Yuan Xing ◽  
Song Lin ◽  
Zhi Qiang Song ◽  
Zhi Qiang Ou

We reported the structural, magnetic and magenetocaloric properties of Mn1.25Fe0.75P0. 50Si0.50Bx(x = 0.01, 0.02 and 0.04) X-ray diffraction patterns show that all compounds crystallize in the hexagonal Fe2P-type crystal structure. Lattice parameter a increases while c decreases with increasing B contents. The Curie temperature of the compounds have been determined, the values are 219, 268 and 323.2 K for x = 0.01, 0.02, 0.04, respectively. The maximum magnetic entropy changes in a field change of 0~1.5 T are 6.1, 5.3 and 3.5J/kg·K for x = 0.01, 0.02 and 0.04, respectively.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Lars Banko ◽  
Phillip M. Maffettone ◽  
Dennis Naujoks ◽  
Daniel Olds ◽  
Alfred Ludwig

AbstractWe apply variational autoencoders (VAE) to X-ray diffraction (XRD) data analysis on both simulated and experimental thin-film data. We show that crystal structure representations learned by a VAE reveal latent information, such as the structural similarity of textured diffraction patterns. While other artificial intelligence (AI) agents are effective at classifying XRD data into known phases, a similarly conditioned VAE is uniquely effective at knowing what it doesn’t know: it can rapidly identify data outside the distribution it was trained on, such as novel phases and mixtures. These capabilities demonstrate that a VAE is a valuable AI agent for aiding materials discovery and understanding XRD measurements both ‘on-the-fly’ and during post hoc analysis.


1964 ◽  
Vol 42 (10) ◽  
pp. 1886-1889 ◽  
Author(s):  
B. Swaroop ◽  
S. N. Flengas

The crystal structure of zirconium trichloride was determined from X-ray diffraction patterns. Zirconium trichloride belongs to the [Formula: see text]space group. The dimensions of the main cell at room temperature are: a = 5.961 ± 0.005 Å and c = 9.669 ± 0.005 Å.The density of zirconium trichloride was measured and gave the value of 2.281 ± 0.075 g/cm3 while, from the X-ray calculations, the value was found to be 2.205 g/cm3.


IUCrJ ◽  
2021 ◽  
Vol 8 (4) ◽  
Author(s):  
Hiroyuki Iwamoto

X-ray fiber diffraction is potentially a powerful technique to study the structure of fibrous materials, such as DNA and synthetic polymers. However, only rotationally averaged diffraction patterns can be recorded and it is difficult to correctly interpret them without the knowledge of esoteric diffraction theories. Here we demonstrate that, in principle, the non-rotationally averaged 3D structure of a fibrous material can be restored from its fiber diffraction pattern. The method is a simple puzzle-solving process and in ideal cases it does not require any prior knowledge about the structure, such as helical symmetry. We believe that the proposed method has a potential to transform the fiber diffraction to a 3D imaging technique, and will be useful for a wide field of life and materials sciences.


2018 ◽  
Vol 74 (8) ◽  
pp. 936-943
Author(s):  
Galina V. Kiriukhina ◽  
Olga V. Yakubovich ◽  
Ekaterina M. Kochetkova ◽  
Olga V. Dimitrova ◽  
Anatoliy S. Volkov

Caesium manganese hexahydrate phosphate, CsMn(H2O)6(PO4), was synthesized under hydrothermal conditions. Its crystal structure was determined from single-crystal X-ray diffraction data. The novel phase crystallizes in the hexagonal space group P63 mc and represents the first manganese member in the struvite morphotropic series, AM(H2O)6(TO4). Its crystal structure is built from Mn(H2O)6 octahedra and PO4 tetrahedra linked into a framework via hydrogen bonding. The large Cs atoms are encapsulated in the framework cuboctahedral cavities. It is shown that the size of the A + ionic radius within the morphotropic series AM(H2O)6(XO4) results is certain types of crystal structures and affects the values of the unit-cell parameters. Structural relationships with Na(H2O)Mg(H2O)6(PO4) and the mineral hazenite, KNa(H2O)2Mg2(H2O)12(PO4)2, are discussed.


1985 ◽  
Vol 49 (353) ◽  
pp. 547-554 ◽  
Author(s):  
M. Shahmiri ◽  
S. Murphy ◽  
D. J. Vaughan

AbstractThe crystal structure and compositional limits of the ternary compound Pt2FeCu (tulameenite), formed either by quenching from above the critical temperature of 1178°C or by slow cooling, have been investigated using X-ray diffraction, transmission electron microscopy, differential thermal analysis and electron probe microanalysis.The crystal structure of Pt2FeCu, established using electron density maps constructed from the measured and calculated intensities of X-ray diffraction patterns of powdered specimens, has the (000) and (½½0) lattice sites occupied by Pt atoms and the (½0½) and (0½½) sites occupied by either Cu or Fe atoms in a random manner. The resulting face-centred tetragonal structure undergoes a disordering transformation at the critical temperature to a postulated non-quenchable face-centred cubic structure. Stresses on quenching, arising from the ordering reaction, are relieved by twinning along {101} planes or by recrystallization along with deformation twinning; always involving grain boundary fracturing.Phase relations in the system Pt-Fe-Cu have been investigated through the construction of isothermal sections at 1000 and 600°C. At 1000°C there is an extensive single phase region of solid solution around Pt2FeCu and extending to the binary composition PtFe. At 600°C the composition Pt2FeCu lies just outside this now reduced area of solid solution in a two-phase field. Comparison of the experimental results with data for tulameenite suggests that some observed compositions may be metastably preserved. The occurrence of fine veinlets of silicate or other gangue minerals in tulameenite is suggested to result from grain boundary fracturing on cooling below the critical temperature of 1178°C and to be evidence of a magmatic origin.


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