scholarly journals Data Validation and Structural Classifications in Powder Diffraction File

2014 ◽  
Vol 70 (a1) ◽  
pp. C1702-C1702
Author(s):  
Soorya Kabekkodu
Keyword(s):  
Crystal Structures ◽  
Powder Diffraction ◽  
Pattern Search ◽  
Published Data ◽  
Powder Diffraction File ◽  
Recent Developments ◽  
Diffraction Patterns ◽  
Quality Mark ◽  
Editorial Review

The new Powder Diffraction File™, housing more than 760,000 diffraction patterns and 200,000 crystal structures, has a wealth of information that a materials scientist can take advantage of in various ways, from materials identification, characterization to design. Various structural and chemical classifications implemented in the database will be presented in detail. These classifications are important in data mining studies and optimizing pattern search/match methods. While using any database in materials characterization, it is important to know the quality of the crystal structure or diffraction pattern found in the database. With varying quality of published data in the literature, database editorial review processes had to adopt rigorous data evaluation methods to classify data based on its quality. Every entry in the Powder Diffraction File™ has a quality mark and editorial comments describing the error and the correction. Results of the analysis of the quality of the crystal structures (~500,000) published over the years will be discussed along with the most common errors found. The recent developments in Powder Diffraction File will be presented.

On the Need for Users of the Powder Diffraction File to Update Regularly

1987 ◽  
Vol 2 (2) ◽  
pp. 84-87 ◽  
Author(s):  
Ron Jenkins ◽  
Mark Holomany ◽  
Winnie Wong-Ng
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Review Process ◽  
Quality Of Data ◽  
Powder Diffraction File ◽  
Editorial Review

AbstractThe International Centre for Diffraction Data has an ongoing program to ensure the quality of data in the Powder Diffraction File (PDF) reflects current requirements of the powder diffraction community. Annual updates are made available, comprising of around 1800 new patterns and 200 replacement patterns, but current statistics indicate that only about 20% of users of the PDF take advantage of these updates. This paper reviews changes which have been inplemented in the editorial review process to continuously monitor and review pattern quality and gives examples of better data which have resulted from these changes.

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.

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.

Crystal structures and reference X-ray powder diffraction patterns of Sr4−xCaxPb2O8 (x=1,2,3)

1998 ◽  
Vol 13 (4) ◽  
pp. 232-240 ◽  
Author(s):  
W. Wong-Ng ◽  
J. A. Kaduk ◽  
W. Greenwood
Keyword(s):  
Crystal Structure ◽  
Solid Solution ◽  
Crystal Structures ◽  
Powder Diffraction ◽  
Alkaline Earth ◽  
Lattice Parameters ◽  
X Ray Diffraction ◽  
Powder Diffraction File ◽  
X Ray ◽  
Diffraction Patterns

The crystal structure of the solid solution alkaline earth plumbate phase Sr4−xCaxPb2O8 was investigated using the X-ray Rietveld technique for x=1, 2, and 3. The lattice parameters a, b, c, and V were found to decrease linearly as the Sr at site 4h was replaced by Ca. The structure features chains of edge-sharing PbO6 octahedra, linked by seven-coordinated (Ca/Sr)–O monocapped trigonal prisms. The structure is similar to that of Pb3O4, which can be reformulated as Pb2IIPbIVO4. X-ray diffraction patterns for the solid solution members SrCa3Pb2O8, Sr2Ca2Pb2O8, and Sr3CaPb2O8 were prepared for inclusion in the Powder Diffraction File.

X-ray powder diffraction patterns of energetic materials

1994 ◽  
Vol 9 (1) ◽  
pp. 2-14 ◽  
Author(s):  
D. B. Sullenger ◽  
J. S. Cantrell ◽  
T. A. Beiter
Keyword(s):  
Crystal Structures ◽  
Powder Diffraction ◽  
Energetic Materials ◽  
Powder Diffraction File ◽  
X Ray ◽  
Diffraction Patterns

X-ray powder diffraction patterns for 18 phases of 14 well-known explosives have been developed in our laboratory. Experimental patterns were obtained with an automated diffractometer for those phases for which samples were available. For phases with known crystal structures, patterns were calculated from the lattice and atomic positional parameters for comparison with the experimental patterns. Eleven of the experimental patterns have been included in Powder Diffraction File (PDF) Sets 40 and 42; four have been accepted but not yet issued. A final experimental pattern shall be submitted this year. In two other instances, since samples of sufficient quantity and/or quality were not available, calculated patterns alone are considered here. A review of the development of the crystallographic knowledge of these substances is given here together with a critique of the patterns and other known patterns of these phases.

X-ray diffraction study and powder patterns of double-perovskites Sr2RSbO6 (R = Pr, Nd, Sm, Eu, Gd, Dy, Ho, Y, Er, Tm, Yb, and Lu)

2014 ◽  
Vol 29 (4) ◽  
pp. 371-378 ◽  
Author(s):  
W. Wong-Ng ◽  
J. A. Kaduk ◽  
M. Luong ◽  
Q. Huang
Keyword(s):  
Diffraction Study ◽  
Crystal Structures ◽  
Powder Diffraction ◽  
Double Perovskite ◽  
Lattice Parameters ◽  
Double Perovskites ◽  
X Ray Diffraction ◽  
Powder Diffraction File ◽  
X Ray ◽  
Diffraction Patterns

The X-ray diffraction powder patterns were prepared and the crystal structures were refined for the double-perovskite series of compounds, Sr2RSbO6 (R = Pr, Nd, Sm, Eu, Gd, Dy, Ho, Y, Er, Tm, Yb, and Lu). We found the structures of the entire Sr2RSbO6 series to be monoclinic with space group P21/n (no. 14), and Z = 2. From R = Lu to Pr, the lattice parameters “a” range from 5.7779(2) to 5.879 05(8) Å, “b” range from 5.7888(2) to 5.969 52(9) Å, “c” range from 8.1767(3) to 8.369 20(12) Å, “β” range from 90.112(2)° to 90.313(1)°, and “V” range from 273.483(4) to 293.714(7) Å3. These lattice parameters follow the well-established trend of “lanthanide contraction”. The R3+ and Sb5+ ions are found to be fully ordered in the double-perovskite arrangement of alternating corner-sharing octahedra in a zigzag fashion. The SrO12, RO6, and SbO6 cages are all found to have distorted coordination environments. Powder diffraction patterns of these compounds have been prepared, submitted, and published in the Powder Diffraction File.

Reference materials for the study of polymorphism and crystallinity in cellulosics

2013 ◽  
Vol 28 (1) ◽  
pp. 18-31 ◽  
Author(s):  
T. G. Fawcett ◽  
C. E. Crowder ◽  
S. N. Kabekkodu ◽  
F. Needham ◽  
J. A. Kaduk ◽  
...  
Keyword(s):  
Powder Diffraction ◽  
Reference Materials ◽  
Reference Data ◽  
Powder Diffraction File ◽  
Material Identification ◽  
Cellulosic Materials ◽  
Chemical Substitution

Eighty specimens of cellulosic materials were analyzed over a period of several years to study the diffraction characteristics resulting from polymorphism, crystallinity, and chemical substitution. The aim of the study was to produce and verify the quality of reference data useful for the diffraction analyses of cellulosic materials. These reference data can be used for material identification, polymorphism, and crystallinity measurements. Overall 13 new references have been characterized for publication in the Powder Diffraction File (PDF) and several others are in the process of publication.

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 reference patterns for Bi1−xPbxOCuSe

2016 ◽  
Vol 31 (3) ◽  
pp. 223-228 ◽  
Author(s):  
W. Wong-Ng ◽  
Y. Yan ◽  
J.A. Kaduk ◽  
X.F. Tang
Keyword(s):  
Cell Volume ◽  
Powder Diffraction ◽  
Ionic Radius ◽  
Unit Cell Volume ◽  
Unit Cell ◽  
Powder Diffraction File ◽  
X Ray ◽  
Natural Superlattice ◽  
Diffraction Patterns ◽  
Pb Substitution

The structures and powder X-ray reference diffraction patterns of the “natural superlattice” series Bi1−xPbxOCuSe (x = 0, 0.02, 0.04, 0.06, 0.08, and 0.10) have been investigated. As the ionic radius of Pb2+ is greater than that of Bi3+, the unit-cell volume of Bi1−xPbxOCuSe increases progressively from x = 0 to 0.1, namely, from 137.868(5) to 139.172(11) Å3, as expected. The structure of Bi1−xPbxOCuSe is built from [Bi2(1−x)Pb2xO2]2(1−x)+ layers normal to the c-axis alternating with [Cu2Se2]2(1−x)− fluorite-like layers. Pb substitution in the Bi site of Bi1−xPbxOCuSe leads to the weakening of the “bonding” between the [Bi2(1−x)Pb2xO2]2(1−x)+ and the [Cu2Se2]2(1−x)− layers. Powder patterns of Bi1−xPbxOCuSe were submitted to be included in the Powder Diffraction File.

On racemic and L-malates: a comparison of their crystal structures

2004 ◽  
Vol 219 (2) ◽  
Author(s):  
Michel Fleck ◽  
Ekkehart Tillmanns ◽  
Ladislav Bohatý ◽  
Peter Held
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Monoclinic Space Group ◽  
Powder Diffraction Data ◽  
X Ray Diffraction ◽  
Powder Diffraction File ◽  
Space Group ◽  
X Ray

AbstractThe crystal structures of eight different L-malates have been determined and refined from single-crystal X-ray diffraction data. The compounds are the monoclinic (space groupIn addition, for all the compounds, powder diffraction data were collected, analysed and submitted to the powder diffraction file (PDF).

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