X-ray Diffraction Resources and Databases

This page gathers a selection of resources for X-ray diffraction (XRD), with a particular focus on powder X-ray diffraction (PXRD), crystallographic databases, reference diffraction patterns, and structural analysis. These resources provide access to crystal structures, experimental and calculated diffraction patterns, online simulation tools, and software for phase identification, structure determination, and Rietveld refinement. Both open-access resources and subscription-based databases are included.

Reference Databases

• Crystallography Open Database (COD) — Open-access collection of experimental crystal structures for inorganic, organic, and metal-organic compounds, available in crystallographic formats such as CIF.
• RRUFF Project — Mineralogical database combining mineral chemistry, crystal data, X-ray diffraction patterns, Raman and infrared spectra, and other characterization results.
• International Centre for Diffraction Data (ICDD) — Powder Diffraction File (PDF) — Major reference database for powder diffraction pattern identification, phase analysis, and materials characterization. Subscription required.
• Inorganic Crystal Structure Database (ICSD) — Curated inorganic crystal structures, including atomic coordinates, unit-cell parameters, space groups, and calculated powder diffraction patterns. Subscription required.
• IUCr — Crystallographic Databases and Related Resources — Directory of major crystallographic databases, including COD, ICSD, the Cambridge Structural Database, and specialized resources.
• Materials Project — Materials database providing calculated structural and diffraction properties for many inorganic compounds.

Online Tools and Diffraction Simulation

• Bilbao Crystallographic Server — Online crystallographic tools for space-group symmetry, subgroup relations, structure transformations, and symmetry analysis.
• IUCr — Powder Diffraction Resources — Entry point for specialized powder diffraction databases, including PowBase and resources for structure determination from powder diffraction.
• XRDlicious — Online calculation of powder X-ray and neutron diffraction patterns from crystal structures, with support for common structural file formats.
• NOMAD Laboratory — Open research-data infrastructure for computational materials science and experimental materials research. Search for relevant diffraction datasets and associated metadata.

Software for Powder Diffraction Analysis

• FullProf Suite — Software suite for Rietveld refinement, profile matching, and magnetic and nuclear structure analysis using X-ray and neutron diffraction.
• GSAS-II — Open-source software for powder diffraction data analysis, indexing, structure solution, Rietveld refinement, and crystallographic visualization.
• JANA2020 — Crystallographic software for structure solution and refinement using single-crystal and powder diffraction data, including incommensurately modulated structures, magnetic structures, twinning, and superspace-group symmetry. Particularly useful for advanced structural investigations and phase transitions.
• TOPAS — Software for powder diffraction analysis, quantitative phase analysis, and Rietveld refinement. Commercial software.
• Profex — Free graphical interface for Rietveld refinement using BGMN, particularly useful for quantitative phase analysis.
• pymatgen — Python library for materials analysis, crystallographic structures, and calculated X-ray and electron diffraction patterns.

Talks, Tutorials, and Educational Resources

• International Union of Crystallography (IUCr) — Crystallography education, publications, scientific meetings, and resources for the crystallographic community.
• GSAS-II — Documentation and Tutorials — Documentation and practical examples covering powder diffraction data processing, indexing, and Rietveld refinement.

These resources support the full workflow of powder diffraction research, from locating reference structures and identifying crystalline phases to simulating diffraction patterns, refining crystal structures, and analysing experimental data. When using a reference database, it is important to distinguish experimental reference patterns from patterns calculated from crystal structures.