THE POTASSIUM SALTS OF FUMARIC ACID: PREPARATION, UNIT CELL CONSTANTS, SPACE GROUPS, AND X-RAY DIFFRACTION POWDER IDENTIFICATION DATA

1961 ◽  
Vol 39 (9) ◽  
pp. 1739-1745 ◽  
Author(s):  
M. P. Gupta ◽  
W. H. Barnes
Keyword(s):  
Single Crystals ◽  
Fumaric Acid ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Potassium Salts ◽  
X Ray ◽  
Space Groups ◽  
Ph Values ◽  
Acid Acid ◽  
Potassium Hydrogen

The preparation of the three crystalline potassium salts of fumaric acid, "acid" potassium hydrogen fumarate (2KHC4H2O4.H2C4H2O4), potassium hydrogen fumarate (KHC4H2O4), and dipotassium fumarate dihydrate (K2C4H2O4.2H2O), is discussed, and suitable pH values for the growth of single crystals of each are given. Unit cell, space group, and X-ray diffraction powder identification data for the three salts are presented.

The structures of marialite (Me6) and meionite (Me93) in space groups P42/n and I4/m, and the absence of phase transitions in the scapolite series

2011 ◽  
Vol 26 (2) ◽  
pp. 119-125 ◽  
Author(s):  
Sytle M. Antao ◽  
Ishmael Hassan
Keyword(s):  
Phase Transitions ◽  
High Resolution ◽  
Crystal Structures ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Space Groups ◽  
Cell Parameters ◽  
The Mean

The crystal structures of marialite (Me6) from Badakhshan, Afghanistan and meionite (Me93) from Mt. Vesuvius, Italy were obtained using synchrotron high-resolution powder X-ray diffraction (HRPXRD) data and Rietveld structure refinements. Their structures were refined in space groups I4/m and P42/n, and similar results were obtained. The Me6 sample has a formula Ca0.24Na3.37K0.24[Al3.16Si8.84O24]Cl0.84(CO3)0.15, and its unit-cell parameters are a=12.047555(7), c=7.563210(6) Å, and V=1097.751(1) Å3. The average ⟨T1-O⟩ distances are 1.599(1) Å in I4/m and 1.600(2) Å in P42/n, indicating that the T1 site contains only Si atoms. In P42/n, the average distances of ⟨T2-O⟩=1.655(2) and ⟨T3-O⟩=1.664(2) Å are distinct and are not equal to each other. However, the mean ⟨T2,3-O⟩=1.659(2) Å in P42/n and is identical to the ⟨T2′-O⟩=1.659(1) Å in I4/m. The ⟨M-O⟩ [7]=2.754(1) Å (M site is coordinated to seven framework O atoms) and M-A=2.914(1) Å; these distances are identical in both space groups. The Me93 sample has a formula of Na0.29Ca3.76[Al5.54Si6.46O24]Cl0.05(SO4)0.02(CO3)0.93, and its unit-cell parameters are a=12.19882(1), c=7.576954(8) Å, and V=1127.535(2) Å3. A similar examination of the Me93 sample also shows that both space groups give similar results; however, the C–O distance is more reasonable in P42/n than in I4/m. Refining the scapolite structure near Me0 or Me100 in I4/m forces the T2 and T3 sites (both with multiplicity 8 in P42/n) to be equivalent and form the T2′ site (with multiplicity 16 in I4/m), but ⟨T2-O⟩ is not equal to ⟨T3-O⟩ in P42/n. Using different space groups for different regions across the series implies phase transitions, which do not occur in the scapolite series.

ζ-Y2[Si2O7]: Ein neuer Strukturtyp in der Yttrialit-Reihe / ζ -Y2[Si2O7]: A New Structure Type within the Yttrialite Series

2006 ◽  
Vol 61 (9) ◽  
pp. 1054-1060 ◽  
Author(s):  
Ingo Hartenbach ◽  
Steffen F. Meier ◽  
Thomas Schleid
Keyword(s):  
Single Crystals ◽  
Title Compound ◽  
Structure Type ◽  
Unit Cell ◽  
Type Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vertex Sharing ◽  
A Minor ◽  
Oxygen Atoms

Abstract During attempts of preparing yttrium oxotellurates(IV) using Y2O3 and TeO2 in YCl3 fluxes, the occasional reaction of these educts with the walls of the evacuated silica ampoules led to colourless, lath-shaped single crystals of Y2[Si2O7] in the new ζ -type structure as a minor by-product which was investigated by X-ray diffraction. The title compound crystallizes monoclinically in the space group P21/m (a = 503.59(5), b = 806.47(8), c = 732.65(7) pm, β = 108.633(6)°) with two formula units per unit cell. The crystallographically unique Y3+ cation is coordinated by seven oxygen atoms (d(Y-O = 221 - 248 pm) arranged in the shape of a slightly distorted monocapped octahedron. The isolated oxodisilicate units [Si2O7]6− consist of two Si4+ cations and seven O2− anions of which five are crystallographically independent. These pyroanions (d(Si-O) = 161 - 168 pm, ∢ (O-Si-O) = 91 - 117°, ∢ (Si-O-Si) = 156°) exhibit an almost perfectly eclipsed conformation built of a horseshoeshaped backbone with the two silicon and three of the oxygen atoms situated on the mirror planes of the unit cell. The remaining four oxide anions complete this [Si2O7]6− entity of two vertex-sharing [SiO4]4− tetrahedra as terminal ligands for silicon. Assembled in planar layers parallel to (−1 0 1), the [Si2O7]6− anions are packed with their wide basal faces of the tetrahedra pointing towards the small waist of the adjacent units and vice versa. The yttrium cations reside between these layers in order to interconnect them three-dimensionally.

Infrared and Raman spectra and X-ray diffraction studies of solid lead(II) carbonates

1983 ◽  
Vol 61 (3) ◽  
pp. 494-502 ◽  
Author(s):  
Murray H. Brooker ◽  
S. Sunder ◽  
Peter Taylor ◽  
Vincent J. Lopata
Keyword(s):  
Unit Cell ◽  
Spectral Features ◽  
Infrared And Raman Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Space Groups ◽  
Carbonate Ions ◽  
Cell Dimensions ◽  
Unit Cell Dimensions ◽  
Sodium And Potassium

Four basic lead carbonates were prepared and identified by X-ray powder diffractometry. These were hydrocerussite (Pb3(OH)2(CO3)2), plumbonacrite (Pb10O(OH)6(CO3)6), and the two adducts MOH•2PbCO3 (M = Na, K). New diffraction data are presented for the latter two compounds; they both have primitive hexagonal lattices with two formula units per unit cell. The unit cell dimensions of the sodium and potassium compounds are a = 5.273 ± 0.002 Å, c = 13.448 ± 0.005 Å and a = 5.348 ± 0.002 Å, c = 13.990 ± 0.005 Å, respectively. Six possible space groups are discussed.Raman and infrared spectra are reported for all four compounds, and compared with those of cerussite (PbCO3); assignment of the spectral features is discussed. Vibrational spectra of the two MOH adducts indicate that they are isostructural, and that the structure contains a well-defined lead sub-lattice, consistent with the X-ray data. The spectra of hydrocerussite and plumbonacrite indicate that lead is present as oxygen-bridged polymeric moieties in these solids. The carbonate ions occupy two and three independent sites in hydrocerussite and plumbonacrite, respectively.

X-Ray Investigations on Some Salts of Hydrazine and Hydrazine Derivatives

1961 ◽  
Vol 5 ◽  
pp. 133-141 ◽  
Author(s):  
M. Stammler ◽  
D. Orcutt
Keyword(s):  
Unit Cell ◽  
X Ray Diffraction ◽  
Monoclinic System ◽  
X Ray ◽  
Space Groups ◽  
Inorganic Acids ◽  
Cell Dimensions ◽  
System Cell ◽  
Diffraction Patterns ◽  
Perchlorate Salt

AbstractThe salts of hydrazine or methyl derivatives of hydrazine were prepared by neutralization of the base with inorganic acids, for instance, HBF4, HClO4, H SO4, and HCl. Upon recrystallization of the product from a suitable solvent, X-ray diffraction patterns were obtained. Hydrazine tetrafluoborate H2N-NH2·HBF4 was found to crystallize in the monoclinic system. Cell dimensions and possible space groups were determined. The corresponding perchlorate salt crystallizes in two forms, one of which is isomorphous with hydrazine tetrafluoborate. The second form seems to be stabilized by small amounts of water.The tetrafluoborate salt was prepared from the 1,1-dimethyl hydrazine. It was found to crystallize in the tetragonal system with a primitive unit cell. The perchlorate salt of this base is isomorphous with the fluoborate but with a slightly larger unit cell. Both materials undergo plastic-like deformation. The general appearance and mechanical properties are similar to those of a hydrocarbon wax. The 1,1-dimethyl hydrazine sulfate and the 1,1-dimethyl hydrazine hydrochloride have a lower symmetry than the HBF4 salt and do not show the wax-like properties of the latter. Based on the study of these chemically related compounds an explanation is offered for the properties of 1,1-dimethyl hydrazine tetrafluoborate in terms of crystalline structure.

scholarly journals Use of a 4-circle goniometer for neutron and X-ray diffractometer in the study of single crystals

2021 ◽  
Vol 16 (4) ◽  
pp. 363-371
Author(s):  
V. A. Sarin
Keyword(s):  
Single Crystals ◽  
Unit Cell ◽  
Neutron Counter ◽  
X Ray Diffraction ◽  
Standard Samples ◽  
X Ray ◽  
Cell Parameters ◽  
Neutron Diffractometer ◽  
Neutron Structure ◽  
Thermal Vibrations

Objectives. This study described the 4-circle goniometer Syntex P1N and its possible applications in X-ray and neutron structure analysis of single crystals.Methods. The 4-circle goniometer Syntex P1N, due to its high-precision mechanical characteristics and individual components from domestic equipment (sets of DRON type X-ray diffractometers), formed the basis for developing an instrument complex for X-ray and neutron-structure studies.Results. The neutron diffractometer was upgraded based on the Syntex P1N goniometer. Therefore, the 10BF3-based end neutron counter, included in the diffractometer kit, was replaced by the 3He-based domestic side counter, SNM-16. Such a significant reduction in the linear dimensions of the detector allowed us to expand the range of measured angles of 2θ from 90° to 140° and increase the accuracy of the measured interplanar distances accordingly. The goniometer was adjusted relative to the primary neutron beam by placing it on a specially designed plate. Highly accurate measured parameters of the unit cell and the intensity of the reflexes were achieved by optimizing the installation geometry and the protection of the goniometer and detector. Based on the Syntex P1N goniometer, an instrument complex for X-ray diffraction studies has also been developed. Both the developed X-ray and the upgraded neutronography facilities were used to perform experiments to measure the unit cell parameters, the coordinates of atoms, and the parameters of their thermal vibrations on several crystals of domestic synthetic samples: diamond C, silicon Si, halite, or rock salt NaCl, and corundum α-Al2O3. An excellent correlation was achieved by comparing the data obtained with the corresponding chemical crystals’ parameters and reference samples recommended by the International Union of Crystallographers.Conclusions. This paper described a neutron installation and a Syntex P1N neutron diffractometer for the study of single crystals. Based on the latter, an instrument complex for X-ray diffraction studies has also been developed. Experiments on standard samples have shown a high level of accuracy in measuring the lattice parameters, the coordinates of atoms, and the parameters of their thermal vibrations on both the X-ray and neutron diffractometers.

Single-Crystal X-Ray Diffraction Study of Na[OCN] at 170 K and its Vibrational Spectra

2010 ◽  
Vol 65 (4) ◽  
pp. 528-532 ◽  
Author(s):  
Olaf Reckeweg ◽  
Armin Schulz ◽  
Brian Leonard ◽  
Francis J. DiSalvo
Keyword(s):  
Single Crystal ◽  
Diffraction Study ◽  
Single Crystals ◽  
Vibrational Spectra ◽  
Unit Cell ◽  
Fermi Resonance ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Rhombohedral Symmetry

The unit cell of Na[OCN] has been determined on single crystals at 170 K to have rhombohedral symmetry with the lattice parameters a = 356.79(10) and c = 1512.3(5) pm (hexagonal setting). According to the only model for which a converging refinement could be achieved, Na[OCN] crystallizes isopointal to β -NaN3 in the space group R¯3m (no. 166, Z = 3) with a statistically disordered [OCN]− anion. The positional coordinates and displacement parameters could not be separated for the O and N end atoms of the triatomic anion. The vibrational spectra show the frequencies typical for an [OCN]− moiety with Fermi resonance between the 2δ and the νsym vibrations for which the undisturbed frequencies were calculated.

Microstructure and crystal symmetry of Pb2Sr2(Y/Ca)Cu3O9−δ

1990 ◽  
Vol 48 (4) ◽  
pp. 64-65
Author(s):  
Y. P. Lin ◽  
J. S. Xue ◽  
J. E. Greedan
Keyword(s):  
Electron Diffraction ◽  
High Temperature Superconductors ◽  
Carbon Film ◽  
Basic Structure ◽  
Crystal Symmetry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Space Groups ◽  
New Family ◽  
Convergent Beam

A new family of high temperature superconductors based on Pb2Sr2YCu3O9−δ has recently been reported. One method of improving Tc has been to replace Y partially with Ca. Although the basic structure of this type of superconductors is known, the detailed structure is still unclear, and various space groups has been proposed. In our work, crystals of Pb2Sr2YCu3O9−δ with dimensions up to 1 × 1 × 0.25.mm and with Tc of 84 K have been grown and their superconducting properties described. The defects and crystal symmetry have been investigated using electron microscopy performed on crushed crystals supported on a holey carbon film.Electron diffraction confirmed x-ray diffraction results which showed that the crystals are primitive orthorhombic with a=0.5383, b=0.5423 and c=1.5765 nm. Convergent Beam Electron Diffraction (CBED) patterns for the and axes are shown in Figs. 1 and 2 respectively.

Fabrication and study the effect of the laser on the properties of the compound Tl2-xHgxBa2-ySryCa2Cu3O10+δ superconductor

2018 ◽  
pp. 168
Author(s):  
A. Kareem Dahash Ali ◽  
Nihad Ali Shafeek
Keyword(s):  
Transition Temperature ◽  
Solid State ◽  
Hydrostatic Pressure ◽  
Electrical Properties ◽  
Co2 Laser ◽  
Temperature Shift ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural And Electrical Properties

This study included the fabrication of    compound (Tl2-xHgxBa2-ySryCa2Cu3O10+δ) in a manner solid state and under hydrostatic pressure ( 8 ton/cm2) and temperature annealing(850°C), and determine the effect of the laser on the structural and electrical properties elements in the compound, and various concentrations of x where (x= 0.1,0.2,0.3 ). Observed by testing the XRD The best ratio of compensation for x is 0.2 as the value of a = b = 5.3899 (A °), c = 36.21 (A °) show that the installation of four-wheel-based type and that the best temperature shift is TC= 142 K  .When you shine a CO2 laser on the models in order to recognize the effect of the laser on these models showed the study of X-ray diffraction of these samples when preparing models with different concentrations of the values ​​of x, the best ratio of compensation is 0.2 which showed an increase in the values ​​of the dimensions of the unit cell a=b = 5.3929 (A °), c = 36.238 (A°). And the best transition temperature after shedding laser is TC=144 K. 

Sign in / Sign up

Export Citation Format

Share Document