QUALX2.0, the updated version of QUALX, is  a computer program able to  identify crystal  phase(s) by powder diffraction data (i.e., qualitative analysis).

Altomare, A.; Cuocci, C.; Giacovazzo, C.; Moliterni, A. & Rizzi, R. , ’QUALX : A computer program for qualitative analysis using powder diffraction data’ (2008), J. Appl. Cryst., 41(4), 815-817.

Altomare, A., Corriero, N., Cuocci, C. , Falcicchio, A. , Moliterni, A. and Rizzi, R.: ‘QUALX2.0: a qualitative phase analysis software using the freely available database POW_COD’ (2015). J. Appl. Cryst. 48, 598-603.

QUALX2.0 is based on the traditional  search–match approach and is  characterized by a high level of automatism and a user-friendly graphic interface. It can: (a) perform  the Kα2 stripping; (b) smooth the experimental pattern; (c) carry out the  2θ0 shift correction; (d)  estimate and subtract the background; (e) locate the experimental diffraction peaks; (f) search  for the database single-phase pattern(s) best matching  the experimental powder diffraction data;  (g) apply suitable restraints (e.g., on chemical composition and/or symmetry and/or cell parameters, ….) in the search; (h) sort the list of candidate phases according to a suitable figure of merit (FoM); (i) perform a semi-quantitative analysis; (j) easily change the default choices and strategies by the graphic interface.

QUALX2.0 can inquiry two alternative databases: 1) PDF-2 [ICDD (2003). The Powder Diffraction File. International Center for Diffraction Data, Newton Square, Pennsylvania, USA];  2) POW_COD, a freely available SQLITE database consisting of entries whose main crystallographic information is generated from the COD database [S. Grazulis et al. (2012). Nucleic Acids Res.  40 (Database Issue), D420–D427], a collection of crystal structures of organic, inorganic, metal-organic compounds and minerals, excluding biopolymers. A subset of POW_COD database, containing only inorganic compounds, is also available (POW_COD_INO database).


Qualitative phase results by QUALX2.0 querying the POW_COD database in an example of a five-phase mixture.


The POW_COD entry of the Silicon structure as visualized by QUALX2.0.



QUALX2.0 dialogue window in case of restraints on chemical composition.


Registered users can freely download here the latest version of QUALX2.0 for Windows and/or the POW_COD database.