Developments in formulation analyses by powder diffraction analysis

2006 ◽  
Vol 21 (2) ◽  
pp. 105-110 ◽  
Author(s):  
T. G. Fawcett ◽  
J. Faber ◽  
F. Needham ◽  
S. N. Kabekkodu ◽  
C. R. Hubbard ◽  
...  

Developments in X-ray analysis hardware and software have combined to dramatically improve the throughput, speed, and accuracy of formulation analyses. We will focus on a complimentary development, the growth and application of a comprehensive database based on the Powder Diffraction File™ (PDF®). The PDF is an edited and standardized combination of several crystallographic databases with ∼497 000 published entries. The comprehensive nature of this database, combined with phase identification and digital pattern simulations, was used to identify complex formulations with crystalline and noncrystalline ingredients. We will show how these parallel developments enhance the ability to correctly identify complex formularies.

2004 ◽  
Vol 19 (4) ◽  
pp. 340-346
Author(s):  
YuanYuan Qiao ◽  
YunFei Xi ◽  
DongTao Zhuo ◽  
Ji Jun Wang ◽  
ShaoFan Lin

A qualitative phase identification system for crystalline mixtures is presented. The system provides up to five-phase qualitative identification using up to nine-peak filtration, and additive full peak matching based on the powder diffraction file of ICDD. It was implemented using Microsoft Visual C++, and runs under most common Windows systems. Screenshots and examples are included.


1984 ◽  
Vol 28 ◽  
pp. 305-308
Author(s):  
Frank N. Blanchard

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.


1991 ◽  
Vol 35 (A) ◽  
pp. 17-23 ◽  
Author(s):  
Gregory J. McCarthy ◽  
Kyli J. Martin ◽  
Jean M. Holzer ◽  
Dean G. Grier ◽  
Wayne M. Syvinski ◽  
...  

AbstractCalculated patterns play an essential role in X-ray powder diffraction analysis. This paper gives examples of their use in qualitative analysis for evaluating and supplementing reference patterns in the ICDD Powder Diffraction File (PDF), in quantitative analysis for calculating Reference Intensity Ratios (RIRs), in ceil parameter refinements for indexing of low-symmetry/large unit cell diffractograms, in powder pattern determination for validating intensities and recognizing preferred orientation, in new materials synthesis for verification of structure type and phase purity, and for modeling the effects of solid solution substitution.


1993 ◽  
Vol 8 (2) ◽  
pp. 107-108 ◽  
Author(s):  
G. Bandoli ◽  
A. Ongaro ◽  
F. Lotto ◽  
M. Rossi

X-ray powder diffraction of Nitrofurantoin C8H6N4O5 reveals that the compound crystallizes in a monoclinic unit cell with the powder data unit cell parameters of a = 7.852(2), b= 6.497(1), c = 18.927(5) Å, β=93.15(2)°, V=964.1(2) Å3. The unit cell dimensions determined by single crystal agree very well with those of powder diffraction analysis. A comparison with the Powder Diffraction File (PDF) 34-1603 indicates that the present data provide a more precise match to the unit cell, include additional weak reflections, along with the indexing of the powder pattern.


2017 ◽  
Vol 32 (2) ◽  
pp. 63-71 ◽  
Author(s):  
T. G. Fawcett ◽  
S. N. Kabekkodu ◽  
J. R. Blanton ◽  
T. N. Blanton

As we celebrate the 75th anniversary of the Powder Diffraction File, the PDF® is still a method for chemical and material analyses. The database and embedded software are designed to solve a range of solid-state material analysis problems that includes phase identification, quantitative analysis, crystallinity, and crystallite size measurements. A versatile platform allows users to interpret X-ray, electron, neutron, or synchrotron diffraction patterns for their analyses. Over several decades as diffraction hardware and software continued to improve, the International Centre for Diffraction Data continues to improve the methods and the PDF database, offering unprecedented analysis capabilities to the modern user.


1976 ◽  
Vol 20 ◽  
pp. 63-73 ◽  
Author(s):  
J. D. Hanawalt

Three powder mixtures, each composed of four or more phases, were submitted for phase identification by x-ray diffraction. Laboratory technicians supplied tables of “d” values and of relative intensities as obtained separately and independently by use of the diffractometer, the Debye camera and the Guinier camera. These tables of diffraction data were “solved” by utilization of the Joint Committee search manuals and reference to the Joint Committee Powder Diffraction File (P.D.F.). The same tables of data were then submitted to the 2dTS:Diffraction Data Tele∼Search for a computer printout of results. Experimental data are also presented which provide a quantitative comparison of the accuracy of measurement of “d” values and of the resolution of Debye cameras vs Guinier cameras, since this information is necessary for efficient search procedures whether by manual or computer methods.


1988 ◽  
Vol 32 ◽  
pp. 269-278
Author(s):  
T. C. Huang ◽  
A. Segmuller ◽  
W. Lee ◽  
V. Lee ◽  
D. Bullock ◽  
...  

AbstractX-ray diffraction techniques have been used for the structure characterization of Y-Ba-Cu-O and Tl-Ca-Ba-Cu-O thin films. A powder diffraction analysis of Y-Ba-Cu-O films showed that the films deposited at 650°C on Si are polycrystalline and have an orthorhambic structure similar to that of the YBa2Cu3O7 bulk superconductors. In addition to the conventional powder diffraction technique, both the rocking curve and the grazing incidence diffraction methods were used to characterize a YBa2Cu3O7 film on (110) SrTiO3 substrate. Results showed that the film was epitaxially grown and aligned with its substrate in a true epitaxy. Phase identification and line broadening analyses of Tl-Ca-Ba-Cu-O films showed that the films are comprised of one or more superconducting phases and probably contain stacking faults.


1992 ◽  
Vol 7 (4) ◽  
pp. 215-218 ◽  
Author(s):  
Sidney S. Pollack ◽  
Gregory J. McCarthy ◽  
Jean M. Holzer

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.


2020 ◽  
Author(s):  
Miranda Maliszka ◽  
◽  
Sabrina Sobel ◽  
Anthony Johnson ◽  
Dennis Radcliffe

2021 ◽  
Vol 36 (1) ◽  
pp. 35-42
Author(s):  
Shivang Bhaskar ◽  
Joseph T. Golab ◽  
James A. Kaduk ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton

The crystal structure of pimecrolimus Form B has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional techniques. Pimecrolimus crystallizes in the space group P21 (#4) with a = 15.28864(7), b = 13.31111(4), c = 10.95529(5) Å, β = 96.1542(3)°, V = 2216.649(9) Å3, and Z = 2. Although there are an intramolecular six-ring hydrogen bond and some larger chain and ring patterns, the crystal structure is dominated by van der Waals interactions. There is a significant difference between the conformation of the Rietveld-refined and the DFT-optimized structures in one portion of the macrocyclic ring. Although weak, intermolecular interactions are apparently important in determining the solid-state conformation. The powder pattern is included in the Powder Diffraction File™ (PDF®) as entry 00-066-1619. This study provides the atomic coordinates to be added to the PDF entry.


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