Significant figures vary throughout the database. In the early years, two significant figures beyond the decimal point were usually the best that could be obtained. Currently, up to seven may be supplied.
Quality Marks (QM) are assigned based upon a number of parameters (see the Help document in the PDF software).
|S or ★
high-quality diffractometer or Guinier data, chemical composition has been well-characterized, intensities have been measured objectively, good range and even spread of intensity, etc.
|d-values are directly the result of Rietveld refinement of the data (only accepted in unusual cases)
|material has significant amorphous content and has a digital diffraction pattern with good signal-to-noise ratio
|pattern has been indexed; therefore, the material is almost certainly single-phase
|calculated from single-crystal structural parameters; structural refinement R-factor was <0.10
|used in the LPF. Prototype structure is an editorial action (i.e., assigned by the PDF editor, not the original source) to assign space group coordinates for entries that have not determined this from the primary literature
|similar to good except no chemical analysis data was submitted to support the materials composition
|does not meet Star, Indexed, or Low-Precision criteria
|data taken on poorly characterized material or data known (or suspected) to be low precision
|calculated from the atomic positions and thermal parameters of an isostructural compound
The original data was experimentally derived. As other sources of data were added to the database, prefix numbers were assigned to the source. Specific subsets of the database can be searched separately and results sets can be sorted by source. This is useful when the compound is a known type (mineral, organic) or a data-gathering method is prefrered (experimental, calculated).
|Old 6-Digit Card
|New 9-Digit Card
|International Centre for Diffraction Data
|FIZ (Fachinformationszentrum) Karlsruhe
|Cambridge Crystallographic Data Centre
|National Institute of Science and Technology
|Linus Pauling File