PDF Product Overview
2012-2013 Products Catalog (.pdf)
Product Summary Flyer (.pdf)
The Powder Diffraction File Difference Flyer (.pdf)
Electron Diffraction Flyer (.pdf)
PDF-4/Organics Flyer (.pdf)
PDF-4+Scholar Flyer (.pdf)
The PDF Databases
Release 2012 of the Powder Diffraction File (PDF) contains 760,019 unique material data sets. Each data set contains diffraction, crystallographic and bibliographic data, as well as experimental, instrument and sampling conditions, and select physical properties in a common standardized format. PDF databases use a Sybase® relational database platform integrated with JAVA™ for point and click data mining, rapid searches and sorts for all materials and materials systems. All ICDD databases use an integrated editorial quality review for all data sets. This is the only crystallographic database that evaluates the quality and provides the results of the assessment to the user in the comment section of each reference. The PDF's large size and comprehensive material coverage is achieved through ICDD's historical sources of powder diffraction data, ICDD's Grant-in-Aid Program, contributions, and bibliographic searches, as well as collaborations with international crystallographic database organizations.
The database is designed and produced in several different formats in order to serve different groups of users.
PDF-2 is a collaborative product between ICDD, FIZ and NIST and is designed for inorganic materials analyses. Many common organic materials from ICDD are added to this database to facilitate rapid material identification. Our data mining software is now integrated into PDF-2, free of charge, as an added value to our customers. (purchase)
PDF-4+ is our most advanced database, designed for both phase identification and quantitative analysis. It contains the data from both the PDF-2 and ICDD's collaboration with MPDS. This database has comprehensive material coverage for inorganic materials and it contains numerous additional features such as digitized patterns, molecular graphics and atomic parameters. Features to enhance the ability to do quantitative analysis have been incorporated into PDF-4+. (purchase)
WebPDF-4 provides the needed portability to the PDF-4+ database via the internet. It enables full functionality of the PDF-4+ database using a high-speed internet connection. WebPDF-4+ is delivered as a USB compatible dongle. (purchase)
PDF-4/Minerals is the most comprehensive collection of mineral data in the world! Ninety-seven percent of all known mineral types, as defined by the International Mineralogical Association (IMA), are represented in the database, as well as many unclassified minerals. PDF-4/Minerals is a subset of the PDF-4+ database, which includes all of the software features incorporated into PDF-4+.
PDF-4/Organics is the world's largest X-ray powder diffraction database for organics. It is designed for a multitude of applications in pharmaceutical, regulatory, specialty chemical, biomaterials and forensic fields. The product has all of the display software and data mining capabilities contained in the PDF-4 family of products.
Printed Books and Indexes include ICDD's experimentally collected diffraction patterns and search manuals. These materials have been produced annually for 62 years and are commonly used as reference books. (purchase)
We are pleased to announce that our prices for the 2012-13 product year will remain constant with two exceptions. The pricing for PDF-4/Organics has been reduced. We simplified the pricing so that it is the same initial license price as PDF-2, PDF-4+ and WebPDF-4+. In addition, we reduced the PDF-4/Organics yearly renewal fees, which are now more attractive. There is a small increase on our site license renewals (PDF-2, PDF-4+, WebPDF-4+) that includes the 2nd to 10th copy renewals and the site/multiyear 2nd to 10th copy renewals.
Figure 1. Display of the increasing value of the Powder Diffraction File and our efforts to maintain pricing. The number of PDF-2/PDF-4 entries are charted against our list and academic pricing over the past 20+ years. The chart tracks the list and academic pricing (right y axis) for PDF-2 (1987-2004), then PDF-4+ (2005-2012) during the history of ICDD CD products. The left axis is the number of entries during this timeframe.
This is our seventh consecutive year of maintaining pricing while increasing value by the dramatic increase in the size and technical capability in the Powder Diffraction File. During the 25-year timeframe charted in Figure 1, the cost for the database has increased 40%, while content has exploded over 600%. Increases in entries, searches and display fields for the last seven annual product releases demonstrate ICDD's commitment and dedication, as a not-for-profit organization, to bring the highest value to the scientific community (see Table 2).
Table 2. Search options, display fields and entry counts for the last six (6) releases of database products. Every PDF database offers self-contained data mining capability using our embedded data mining software.
The Powder Diffraction File databases are designed for material identification and characterization. The design is based on continuous input from members and users of the PDF. The content of the PDF arises from experimental data sourced from powder experimental and single crystal crystallographic determinations. The diffraction data are sourced from grants and the bibliographic eff orts of the ICDD. Single crystal data are sourced from ICDD's bibliographic literature extraction and strategic collaborations with other database organizations. There are two primary database families, PDF-2 and PDF-4. PDF-2 is designed to work with automated diffractometers for rapid material identification; PDF-4 products are designed for identification and quantitative analysis. PDF-4 databases include atomic coordinates and embedded structure factors as well as full digital patterns to enable both identification and quantitative analysis. PDF-4 productsalso include experimental digital patterns of noncrystalline materials,such as most clays and industrially important polymers.
There are several important design features that enhance material identification in the ICDD databases.
The Powder Diffraction File Difference:
- All data are standardized, which allows data from different sources and global publications to be compared.
- All data from all sources are reviewed for quality. Quality standards and review procedures have been established for different categories of data. ICDD databases are the only crystallographic databases in the world with quality marks and quality review processes that are ISO 9001 certified.
- Data are reviewed by editors and editorial field experts and receive structural classification and classifications into material subfiles. This enables materials and analytical laboratories to quickly and efficiently identify commercial materials in their analyses.
- The PDF constantly adds new material data sets through ICDD's own bibliographic effort and those of our collaboration partners. Emerging fields such as modulated structures, thermoelectrics, display and energy storage materials are enhanced with annual additions to the database. New minerals, metals and alloys, ceramics and pharmaceuticals are continually being added as well.
- The combination of a relational database, designed searches, JAVA™ point and click interfaces, and extensive content provides users with powerful data mining tools. These tools can be used to enhance material identification, identify minor and trace phases, evaluate crystallinity and crystallite size, and to identify the most appropriate structures and patterns for Rietveld and other types of total pattern analyses.
Figure 2. Data entries by publication year for minerals (top, PDF-4+ 2012) and pharmaceuticals (bottom, PDF-4/Organics 2012) The data reflect continuous global production, as well as classification efforts by ICDD editors.
Evolution of the Powder Diffraction File
The Powder Diffraction File is always evolving in order to meet the materials analysis needs of the global scientific community. Advances in software, hardware (particularly sources and detectors) and computer technology in the last decade have resulted in improvements in throughput and overall lower detection limits. In turn, this has necessitated the need for higher quality data to do more complex multiphase analyses, and different types of data (full digital patterns, atomic parameters) to perform total pattern analyses. An explosion in advanced detector technology has resulted in more diffraction data being collected on high dynamic range, high sensitivity, and two dimensional detectors. There has also been growth in global neutron and synchrotron source facilities. In response to this changing environment, ICDD databases now include tools for users to evaluate different types of data that can be collected on different types of detectors using a range of different sources for their diffraction experiments. Examples are shown in Figure 3 where diffraction data are displayed as ED spot patterns, ring patterns, EBSD patterns and conventional diffractograms. The database contains embedded scattering factor tables for neutron, X-ray and electron diffraction sources. An example of a calculated synchrotron pattern is shown in Figure 3(D). All calculations are accompanied by menu options where the user can select wavelength types and various instrumental parameters. A crystallite size calculation was added in 2007 and an orientation function was added in 2011.
In recent years, the ICDD has decided to include several types of less crystalline materials to the database. This includes two-dimensional clays, mixed crystallinity polymers, amorphous materials, and nanomaterials. These additions were in direct response to our user surveys that indicated global scientists are performing nanomaterial, crystallinity and crystallite size analyses on a frequent basis.
Figure 3. The PDF Entry tool bar can be used to present diffraction data in different formats. In this example of a metal-organic framework (MOF) material, from top left and rotating clockwise, there is (A) an electron diffraction spot pattern; (B) an X-ray diffraction ring pattern; (C) an electron backscatter diffraction (EBSD) pattern; (D) a synchrotron pattern; (E) a calculated digital pattern and the experimental digital pattern (PD3) on the same graphic; and finally (F) the crystal and molecular structure display. The EBSD and spot patterns are specific to electron diffraction (A and C). Other patterns (B, D, E) can be expressed as neutron, X-ray, or electron diffraction. The spot pattern and EBSD pattern show the (010) projection. All diffraction displays are interactive with menus for instrumental and experimental conditions.
Nanomaterials have domain sizes of 100 Å or less where a significant portion of the bulk materials is on the surface. These materials often exhibit mixed crystalline states. Diffraction is a very powerful tool to distinguish between the amorphous, disordered, and crystalline states that comprise nanomaterials design. However, great care needs to be taken in interpreting diffraction patterns of noncrystalline materials since they lack the precision and accuracy inherent in the sharp diffraction peaks of crystalline materials. Working in conjunction with our member scientists, the ICDD has developed quality evaluation methods for noncrystalline materials and established two quality marks: "good" (G) and "minimal acceptable" (M). These marks reflect the quality of supporting data used in the interpretation of the diffraction pattern. For example, an amorphous material with a quality mark of (G) would need independent analytical analyses verifying the stated composition, or TGA/DSC analyses confirming the physical stability, presence of a glass transition, and the absence of moisture. In the example at the bottom of Figure 4 for a ceria nanomaterial, the nano size has been confirmed by small angle X-ray scattering, pair distribution function analysis and electron microscopy. In the case of substituted celluloses as shown in Figure 4, we have nmr data confirming the substitution level and experimental processing details that explain the variances in crystallinity. In the case of the polystyrenes, we have information on the tacticity of the materials. In all cases for noncrystalline materials, we record the specimen preparation conditions and instrumental conditions since different conditions can change the pattern. A quality mark of (G) designates that the editors are satisfied the pattern presented is representative of both the diffraction conditions given and the stated chemistry and have confidence in reproducibility, if the user uses similar instrumental conditions. If a quality mark of (M) is assigned, it indicates that the ICDD received some support documentation, but it was insufficient for structural interpretations (i.e., amorphous, nanocrystalline, isotactic, atactic) and classification of the material.
The ICDD has been adding noncrystalline materials since 2006; however, the quality mark assignments with associated display fields and search algorithms were added for Release 2012.
Figure 4. Experimental digital patterns are particularly useful for characterizing noncrystalline materials. From the top: montmorillite clays exhibiting varying interlayer distances ((001) in yellow box), several cellulose triacetates of varying crystallinity that differ with processing treatments, polystyrene monomers, and copolymers that vary in crystallinity and tacticity. The patterns on the bottom compare experimental data for a nano ceria (courtesy Tom Blanton, Eastman Kodak Company) to a calculated pattern with a 12 Å crystallite size.