High-level guide for using deCIFer in Ouro, with embedded starter PXRD example files.
deCIFer predicts a candidate crystal structure in CIF format from a powder X-ray diffraction (PXRD) pattern. It is useful when you already have an experimental or simulated diffraction pattern and want a fast starting structure to inspect, compare, or refine.
The model conditions on Q = 4π sin(θ)/λ in Å⁻¹, resampled onto 0–10 Å⁻¹. If column 1 of your file is 2θ in degrees, the route converts it to Q first. Set x_axis to q or 2theta when you know the axis. For 2θ files, pass wavelength in Å (Cu Kα 1.5406 is the default).
Open the service
Transformer-based model for crystal structure prediction, generating Crystallographic Information Files (CIFs) directly from powder X-ray diffraction (PXRD) data. The model conditions on Q in Å⁻¹ (0–10). 2θ files are converted using wavelength (Cu Kα default).
Accepts an .xy/.xye file and runs deCIFer to predict a CIF file. Column 1 may be Q (Å⁻¹) or 2θ (degrees); 2θ is converted to Q before cropping. Pass composition when known.
What to upload
A text-based PXRD file in .xy or .xye format, with two numeric columns for position and intensity, covering the main peaks of interest.
Helpful inputs:
composition, when you know the chemical formula. This is the most important optional field — without it the model often invents chemistry even when the cell is right.
spacegroup, when you already have a strong symmetry prior.
x_axis: auto, q, or 2theta.
wavelength: Å, used for 2θ data.
What you get back
One generated CIF file per run. Treat it as a candidate structure, not a final answer. The app runs asynchronously in Ouro, so the request is accepted first and the CIF appears after the run completes.
Quick start
Open the deCIFer service.
Upload a PXRD file.
Add a composition prompt if you know it.
Set x_axis to 2theta and wavelength if the file is in degrees.
Submit the run.
Review the returned CIF as a candidate structure, not a final answer.
Example files
These uploaded files are good starting points for first runs.
Si.xy — already Q-space. Suggested composition prompt: Si
PXRD sample file, from Tackling Real-World Crystal Structure Prediction from Powder X-ray Diffraction Data by Frederik Lizak Johansen and Adam F. Sapnik et. al.
Fe2O3.xy — 2θ (about 5–80°). Suggested composition prompt: Fe2O3
PXRD sample file, from Tackling Real-World Crystal Structure Prediction from Powder X-ray Diffraction Data by Frederik Lizak Johansen and Adam F. Sapnik et. al.
CrystallineCeO2.xye — already Q-space. Suggested composition prompt: Ce4O8
PXRD sample file, from Tackling Real-World Crystal Structure Prediction from Powder X-ray Diffraction Data by Frederik Lizak Johansen and Adam F. Sapnik et. al.
Tips for better results
Start with the composition prompt when you know it.
Set x_axis explicitly when you know whether column 1 is Q or 2θ.
Only add a space group prompt when you have a strong prior.
Use a few trials (n_trials=3 or more). The published experimental protocol draws many samples.
Compare the generated CIF against known phases, symmetry expectations, and peak positions.
Practical note
deCIFer is best used as a structure proposal tool. Experimental validation and downstream refinement are still important before treating the output as a final structure solution. q_min_crop / q_max_crop are Q bounds in Å⁻¹, applied after any 2θ conversion.