An Application of Calculated X-Ray Diffraction Patterns in the Analysis of Reference Powder Data: Trivalent Metal Sulfates

1992 ◽  
Vol 7 (4) ◽  
pp. 215-218 ◽  
Author(s):  
Sidney S. Pollack ◽  
Gregory J. McCarthy ◽  
Jean M. Holzer
Keyword(s):  
Powder Diffraction ◽  
Structure Data ◽  
The Other ◽  
Phase Identification ◽  
X Ray Diffraction ◽  
Trivalent Metal ◽  
Powder Diffraction File ◽  
X Ray ◽  
Cell Parameters ◽  
Diffraction Patterns

AbstractPowder diffraction patterns have been calculated for nine isostructural rhombohedral M2(SO4)3 (M = Sc, Ti, V, Cr, Fe, Ga, Y, Rh, In) phases, and for four isostructural monoclinic M2(SO4)3 (M = V, Fe, In, Tl) phases. The pattern for monoclinic Fe2(SO4)3 is the first reported for this phase. Because structure data are available only for the two Fe2(SO4)3 polymorphs, the powder patterns of the other trivalent metal sulfates were approximated using the structure data of the isostructural Fe phases with the scattering factors and previously determined cell parameters of the various metal sulfates. These calculated patterns are termed an approximation by isostruduralism.The calculated patterns were used to evaluate reference powder data for these phases in the Powder Diffraction File (PDF). All but two of the PDF patterns were found to differ substantially from the calculated patterns in the stronger peaks used for identification, and to be missing weak peaks that may be confused for impurities during phase identification.

Powder X-Ray Data for Synthetic Anhydrous Sodium Zirconium Silicates

1987 ◽  
Vol 2 (3) ◽  
pp. 176-179 ◽  
Author(s):  
G. Wilson ◽  
F. P. Glasser
Keyword(s):  
Solid State ◽  
Diffraction Pattern ◽  
Powder Diffraction ◽  
Solid State Reaction ◽  
The Other ◽  
X Ray Diffraction ◽  
Powder Diffraction File ◽  
X Ray ◽  
Sodium Zirconium ◽  
Diffraction Patterns

AbstractA systematic survey of phase formation in the Na2O-ZrO2-SiO2 system has revealed inconsistencies in the number and identity of ternary phases, and of their X-ray powder data. The phases Na2ZrSiO5, Na4Zr2Si3O12, Na2ZrSi2O7 and Na2ZrSi4O11 were prepared by solid-state reaction and their experimental X-ray diffraction patterns measured. Calculated X-ray diffraction patterns were generated by computer, using published crystallographic data, and critically compared with the experimentally observed values. The unit-cell constants were redefined to a greater accuracy than the presently accepted values published in the Powder Diffraction File. Only Na4Zr2Si3O12 produced an X-ray diffraction pattern which agreed with that previously published; those from the other phases were significantly different in both the intensities and positions of the reflections. Data for synthetic Na2ZrSi4O11 identical to the mineral vlasovite are reported.

The Quality of X-ray Diffraction Standards for Phosphate Minerals and the Degree of Success in Computer Identification

1984 ◽  
Vol 28 ◽  
pp. 305-308
Author(s):  
Frank N. Blanchard
Keyword(s):  
Data Base ◽  
Powder Diffraction ◽  
Data Reduction ◽  
Phase Identification ◽  
X Ray Diffraction ◽  
Powder Diffraction File ◽  
X Ray ◽  
Diffraction Patterns ◽  
Computer Identification

Sixty-five years ago Hull first described X-ray powder diffraction as a means of phase identification, and 45 years ago Hannawalt and co-workers compiled the first catalogue of powder diffraction patterns, which has evolved into a file of about 44,000 patterns (the X-ray Powder Diffraction File or PDF). The Hannawalt method of manually searching the PDF is a time-tested, effective tool in seeking a match between an unknown pattern and its correct counterpart(s) in the PDF. Recently, computerized powder diffractometers with software to perform data reduction and search the PDF have become relatively common, and these systems offer tremendous potential for rapid and accurate phase identification in simple and complex systems where the data base may include 44,000 patterns.

Evaluation of Reference X-ray Diffraction Patterns in the ICDD Powder Diffraction File

1990 ◽  
Vol 34 ◽  
pp. 369-376
Author(s):  
G. J. McCarthy ◽  
J. M. Holzer ◽  
W. M. Syvinski ◽  
K. J. Martin ◽  
R. G. Garvey
Keyword(s):  
Powder Diffraction ◽  
X Ray Diffraction ◽  
Powder Diffraction File ◽  
Cd Rom ◽  
X Ray ◽  
Binary Oxides ◽  
Diffraction Patterns ◽  
Input Format ◽  
Good Agreement

AbstractProcedures and tools for evaluation of reference x-ray powder patterns in the JCPDSICDD Powder Diffraction File are illustrated by a review of air-stable binary oxides. The reference patterns are evaluated using an available microcomputer version of the NBS*A1DS83 editorial program and PDF patterns retrieved directly from the CD-ROM in the program's input format. The patterns are compared to calculated and experimental diffractograms. The majority of the oxide patterns have been found to be in good agreement with the calculated and observed diffractograms, but are often missing some weak reflections routinely observed with a modern diffractometer. These weak reflections are added to the PDF pattern. For the remainder of the phases, patterns are redetermined.

X-ray powder diffraction studies of (BaxSr1−x)2Co2Fe12O22 and (BaxSr1−x)Co2Fe16O27

2015 ◽  
Vol 30 (2) ◽  
pp. 139-148 ◽  
Author(s):  
W. Wong-Ng ◽  
G. Liu ◽  
Y. Yan ◽  
K. R. Talley ◽  
J. A. Kaduk
Keyword(s):  
Seebeck Coefficient ◽  
Powder Diffraction ◽  
Lattice Parameters ◽  
Hexagonal Ferrite ◽  
Layered Compounds ◽  
X Ray Diffraction ◽  
Powder Diffraction File ◽  
Space Group ◽  
X Ray ◽  
Diffraction Patterns

X-ray structural characterization and X-ray reference powder patterns have been determined for two series of iron- and cobalt-containing layered compounds (BaxSr1−x)2Co2Fe12O22 (x = 0.2, 0.4, 0.6, 0.8) and (BaxSr1−x)Co2Fe16O27 (x = 0.2, 0.4, 0.6, 0.8). The (BaxSr1−x)2Co2Fe12O22 series of compounds crystallized in the space group R$\bar 3$m (No. 166), with Z = 3. The structure is essentially that of the Y-type hexagonal ferrite, BaM2+Fe63+O11. The lattice parameters range from a = 5.859 15(8) to 5.843 72(8) Å, and c = 43.4975(9) to 43.3516(9) Å for x = 0.2 to 0.8, respectively. The (BaxSr1−x)Co2Fe16O27 series (W-type hexagonal ferrite) crystallized in the space group P63/mmc (No. 194) and Z = 2. The lattice parameters range from a = 5.902 05(12) to 5.8979(2) Å and c = 32.9002(10) to 32.8110(13) Å for x = 0.2 to 0.8. Results of measurements of the Seebeck coefficient and resistivity of these two sets of samples indicated that they are insulators. Powder X-ray diffraction patterns of these two series of compounds have been submitted to be included in the Powder Diffraction File.

Evaluation of Reference X-Ray Diffraction Patterns in the ICDD Powder Diffraction File

1991 ◽  
pp. 369-376
Author(s):  
G. J. McCarthy ◽  
J. M. Holzer ◽  
W. M. Syvinski ◽  
K. J. Martin ◽  
R. G. Garvey
Keyword(s):  
Powder Diffraction ◽  
X Ray Diffraction ◽  
Powder Diffraction File ◽  
X Ray ◽  
Diffraction Patterns

Powder diffraction investigations of naphthalenesulfonic acids and their complexes with DMAN

2004 ◽  
Vol 19 (4) ◽  
pp. 378-384
Author(s):  
A. Rafalska-Lasocha ◽  
M. Grzywa ◽  
B. Włodarczyk-Gajda ◽  
W. Lasocha
Keyword(s):  
Powder Diffraction ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Monoclinic System ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Acid Hydrate ◽  
M 12 ◽  
Diffraction Patterns

The X-ray diffraction patterns of two organic acids 1-naphthalenesulfonic acid dihydrate and 2-naphthalenesulfonic acid hydrate were measured at room temperature. Complexes of these acids with 1,8-bis(dimethylamino)naphthalene (DMAN) were synthesized, purified and investigated by means of X-ray powder diffraction. 1-Naphthalenesulfonic acid dihydrate as well as its complex with 1,8-bis(dimethylamino)naphthalene crystallize in the monoclinic system with unit cell parameters refined to a=0.91531(8) nm, b=0.7919(1) nm, c=0.8184(1) nm, β=101.618(9)° space group P21/m (11) and a=1.7781(4) nm, b=2.0122(4) nm, c=1.2337(2) nm, β=96.54(3)°, space group C2/m (12), respectively. 2-Naphthalenesulfonic acid hydrate crystallizes in the orthorhombic system with a=2.2749(3) nm, b=0.7745(1) nm, c=0.591 36(9) nm, space group Pnma, whereas its complex with 1,8-bis(dimethylamino)naphthalene crystallizes in the triclinic system a=1.3969(6) nm, b=1.4292(5) nm, c=1.1741(6) nm, α=90.93(3)°, β=98.14(3)°, γ=113.93(3)°, space group P-1 (2).

Barium hollandite-type compounds BaxFe2xTi8−2xO16 with x=1.143 and 1.333

1999 ◽  
Vol 14 (1) ◽  
pp. 31-35 ◽  
Author(s):  
J. M. Loezos ◽  
T. A. Vanderah ◽  
A. R. Drews
Keyword(s):  
Phase Transition ◽  
High Temperature ◽  
Powder Diffraction ◽  
Framework Structure ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Diffraction Patterns ◽  
Acta Crystallogr

Experimental X-ray powder diffraction patterns and refined unit cell parameters for two barium hollandite-type compounds, BaxFe2xTi8−2xO16, with x=1.143 and 1.333, are reported here. Compared to the tetragonal parent structure, both compounds exhibit monoclinic distortions that increase with Ba content [Ba1.333Fe2.666Ti5.334O16: a=10.2328(8), b=2.9777(4), c=9.899(1) Å, β=91.04(1)°, V=301.58(5) Å3, Z=1, ρcalc=4.64 g/cc; Ba1.143Fe2.286Ti5.714O16: a=10.1066(6), b=2.9690(3), c=10.064(2) Å, β=90.077(6)°, V=301.98(4) Å3, Z=1, ρcalc=4.48 g/cc]. The X-ray powder patterns for both phases contain a number of broad, weak superlattice peaks attributed to ordering of the Ba2+ ions within the tunnels of the hollandite framework structure. According to the criteria developed by Cheary and Squadrito [Acta Crystallogr. B 45, 205 (1989)], the observed positions of the (0k1)/(1k0) superlattice peaks are consistent with the nominal x-values of both compounds, and the k values calculated from the corresponding d-spacings suggest that the Ba ordering within the tunnels is commensurate for x=1.333 and incommensurate for x=1.143. High-temperature X-ray diffraction data indicate that the x=1.333 compound undergoes a monoclinic→tetragonal phase transition between 310 and 360 °C.

X-Ray Powder Data for Tetracycline-urea Tetrahydrate, C23H36N4O13 and Tetracycline Hexahydrate, C22H24N2O8·6H2O

1989 ◽  
Vol 4 (3) ◽  
pp. 168-171
Author(s):  
Frank N. Blanchard ◽  
Gus J. Palenik
Keyword(s):  
Powder Diffraction ◽  
Objective Evaluation ◽  
Good Resolution ◽  
Close Correspondence ◽  
Unit Cell Parameters ◽  
Powder Diffraction File ◽  
X Ray ◽  
Cell Parameters ◽  
Low Intensity ◽  
Diffraction Patterns

AbstractIndexed powder diffraction patterns and related crystallographic data are reported for tetracycline-urea tetrahydrate and tetracycline hexahydrate, neither of which is represented in the X-ray Powder Diffraction File. Objective evaluation of the data indicates high precision of d-spacings and unit-cell parameters, intensities that are acceptably reproducible, sensitivity for low intensity reflections, good resolution of closely spaced reflections, and close correspondence with calculated patterns.

Structures and X-ray diffraction patterns of compounds in the Sr–Nd–Cu–O system

1995 ◽  
Vol 10 (1) ◽  
pp. 56-66 ◽  
Author(s):  
Winnie Wong-Ng
Keyword(s):  
Crystal Structures ◽  
Powder Diffraction ◽  
X Ray Diffraction ◽  
Powder Diffraction File ◽  
Comprehensive Review ◽  
X Ray ◽  
Diffraction Patterns ◽  
Ternary Oxides

A comprehensive review of phases found in the Sr–Nd–Cu–O system which contains the high Tc superconductor phase Sr1−xNdxCuO2 has been prepared. This paper summarizes the crystal structures reported in the literature and the X-ray powder diffraction patterns reported in the ICDD Powder Diffraction File (PDF). In order to supplement the PDF with new patterns, calculated X-ray powder diffraction patterns generated from reported structures are provided for five ternary oxides: Sr0.86Nd0.14CuO2, SrNdCuO3.5, Sr6Nd3Cu6O17, Sr2NdCu2O5.66, and Sr1.2Nd1.8Cu2O6.

Computer Identification Techniques for Crystalline Compounds Using the JCPDS Powder Diffraction File as a Data Reference

1976 ◽  
Vol 20 ◽  
pp. 103-112
Author(s):  
George Van Trump ◽  
Phoebe L. Hauff
Keyword(s):  
Data Base ◽  
Powder Diffraction ◽  
Time Sharing ◽  
X Ray Diffraction ◽  
Powder Diffraction File ◽  
X Ray ◽  
Jcpds Powder Diffraction File ◽  
Diffraction Patterns ◽  
Identification Techniques ◽  
Computer Identification

The mineralogy laboratory of the U.S. Geological Survey in Denver has developed a series of time-sharing oriented computer programs which aid in the identification of crystalline compounds from chemical and X-ray diffraction data. These programs operate on a data base compiled primarily from the Powder Diffraction File of the Joint Committee on Powder Diffraction Standards (JCPDS). Diagrammatic X-ray diffraction patterns and various search tables are products of these programs. Additional programs can retrieve information from the data base by chemical formula components or Powder Diffraction File number, and can search and match reflections of an unknown against reference patterns.

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