: Some legacy versions (like the old PDF-2) may float around on "abandonware" sites, but these lack the modern interface, updated entries, and compatibility with current XRD software (like HighScore Plus or Jade).
| Database | Content | Access | |----------|---------|--------| | | >500,000 structures | crystallography.net – free download | | AMCSD (American Mineralogist Crystal Structure Database) | Mineral structures | rruff.geo.arizona.edu | | SpringerMaterials (free demo) | Limited patterns | Register for limited queries | | PubChem (for organics) | Calculated patterns | Download .cif → simulate pattern | Icdd Pdf-4 Database Free Download
The is a commercial product and is not available for free download as a complete database . The International Centre for Diffraction Data ( ICDD ) requires a paid license for its PDF-4 series (including PDF-4+, PDF-4/Minerals, and PDF-4/Axiom). : Some legacy versions (like the old PDF-2)
Common versions: