ICDD’s Mission
To be the world center for quality diffraction data, meeting the needs of the technical community.

To promote the application of materials characterization methods in science and technology,
by providing a forum for the exchange of ideas and information.

The processes for developing the databases of the Powder Diffraction File are focused on continuous improvement in both comprehensive coverage and data quality. Release 2007 PDF products contain more data, higher quality data, new data on new materials, and enhanced capabilities for materials analysis.

New Data, More Data, Enhanced Analysis Capabilities
The modern Powder Diffraction File, PDF-4, is now a combination of data received from several global databases, statistically analyzed and edited into a standardized easily searched format. New data with new materials are added every year and data quality continuously improves as a result of advanced instrumentation and experimental methods combined with editorial review. The ICDD measures improvements and data quality through an editorial system that standardizes, reviews and statistically analyzes every data set. The results of these analyses are contained in each database through quality marks and millions of lines of editorial comments. The quality evaluation of every entry is a unique attribute of the Powder Diffraction File.

New Data
The Powder Diffraction File continues to grow with the addition of new entries in Release 2007 products.

• 13,467 new entries in PDF-2
• 17,359 new entries in PDF-4+
• 25,891 new entries in PDF4/Organics

The large number of new entries are a result of a series of strategic collaborations with international
database organizations.
Collaborative partners include:

• Cambridge Crystallographic Data Centre (CCDC),Cambridge, UK—CSD Database
• Fachinformationszentrum Karlsruhe (FIZ),Karlsruhe, Germany—ICSD Database
• National Institute of Standards and Technology (NIST), Gaithersburg, Maryland
• Material Phases Data System (MPDS), Vitznau, Switzerland—LPF Database

The net result has been explosive growth in the size of the PDF and a dramatic change in annual data received by the ICDD. The PDF now encompasses annual additions from multiple bibliographic efforts associated with each organization, as well as data received from ICDD grantees. After our quality review on more than 50,000 entries, ICDD processed 41,877 new entries for Release 2007.

Global coverage has also resulted in many unique materials being added to the PDF in recent years. This can be seen in the increased number of entries with unique empirical formulae in the database, impressive increases in the content of many subfiles, and increases in the number of primary patterns, authors, and title citations. The ICDD grant program focuses on commercially important materials resulting in catalysts, ceramics, natural products and pharmaceuticals being added to the PDF every year.

More Data
Each PDF product has increased in size with new data additions. An editorial review process analyzes entries and eliminates duplicates that arise from merging different data sources. MPDS entries, containing more data, replace duplicate reference patterns and citations from FIZ and NIST entries in PDF-4+. This is the fundamental reason why FIZ and NIST sourced data decrease in number when comparing PDF-2 and PDF-4+. The large increase in entries represents new data on new materials, as described above, as well as higher quality entries on existing materials and new data on polymorphic forms.

Enhanced Analysis Capability
Two major editorial efforts resulted in enhanced capabilities for Release 2007 products. These involved subfile improvements and cross-references. The subfile improvements are aimed at improving subfile search identification and data mining processes. Cross-references direct users to similar entries with the same chemistry in the same structural family within the PDF. Cross-references link experimental powder data and single crystal data, as well as primary references and alternate references.

Improved Subfile Content
ICDD’s historic PDF subfile system was uniquely characteristic to the data sourced from powder diffraction experiments. This system has been applied to all sources of data used in the Powder Diffraction File. In order to compare entries within each subfile to the entire database population, ICDD developed a program to assist editors in identifying subfile candidates from single crystal sources (i.e., LPF, CSD, NIST and ICSD). The results were approved by ICDD’s editors and editorial task teams consisting of field experts. This system of automated analysis followed by editorial review was implemented this year and resulted in a dramatic increase in subfile populations. The subfile additions will improve the efficiency and accuracy of subfile-based search match identifications. The additions are heavily concentrated with single crystal determinations resulting in the increased number of phases with I/Ic values in all databases and entries with atomic coordinates in PDF-4+ and PDF-4/Minerals. This should benefit users performing quantitative analyses.

Improved Quantitative Analysis
In all PDF products, cross-references link entries without I/Ic values to entries that have these data. This allows all entries to be used in a phase identification process with links to the best available references for quantitative analysis. The “best available” reference is defined by a detailed statistical analysis combined with editorial review. Quality parameters are calculated for every entry and used for assigning primary and alternate assignments and establishing cross-references. Software developers use the cross-references for automated quantitative analysis. Release 2007 products contain over 190,000 crossreferences. In PDF-4+, the cross-referencing system is also used to link entries without atomic coordinates to those that contain these parameters, resulting in improved Rietveld analysis capability.

The programs developed to analyze quality and assign crossreferences are now incorporated into the editorial process. New cross-references will be added with every annual database release.

The PDF Databases
Release 2007 of the Powder Diffraction File contains over 550,000 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.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 the ICDD are added to this database to facilitate rapid material identification.

PDF-4+ is an advanced database containing 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 features such as digitized patterns, molecular graphics and atomic parameters. Many new features have been incorporated into PDF-4+ to enhance the ability to do quantitative analysis by any of three methods: Rietveld Analysis, Reference Intensity Ratio (RIR) method or Total Pattern Analysis.

PDF-4/Minerals is a subset of PDF-4+, which includes the new features incorporated into PDF-4+.

PDF-4/Organics is a collaborative product between the ICDD and CCDC. It is designed to identify organic and organometallic materials and it contains a few thousand inorganic materials, primarily pharmaceutical excipients to help with formulation analyses and identification.

Printed Books and Indexes include ICDD’s experimentally collected diffraction patterns and search manuals. These materials have been produced annually for 57 years and are commonly used as reference books.