Automatic structure determination from powder data withEXPO2004

Abstract

EXPO2004 is the updated version of the EXPO program [Altomare et al. (1999). J. Appl. Cryst. 32, 339–340]. The traditional steps of the ab initio powder solution process are performed automatically: indexing, space‐group determination, decomposition of the pattern for extracting the observed structure‐factor moduli, structure solution by direct methods, model refinement by Rietveld technique. Special strategies may be applied to improve both the estimates of the extracted structure‐factor moduli and the quality of the structure model. In addition, the use of special procedures exploiting available supplementary information on molecular geometry can be successfully adopted. The graphical interface has also been improved.

New Layered Rare‐Earth Hydroxides with Anion‐Exchange Properties

“…A direct method by using the program EXPO2004 [11] was first applied to derive the positions of the eight Eu atoms. The other lighter species (OH, H 2 O, Cl) were estimated through an electron-density distribution analysis by employing the maximum-entropy method (MEM)/Rietveld technique.…”

Synthesis and characterization of inorganic‐organic ZnS(aminopropane)n composite materials

“…The crystal structure of this compound was solved using powder diffraction methods exclusively. Positions of heavy atoms and atoms of organic part were found using direct methods and global optimisation techniques, respectively, using the EXPO2004 [14] and FOX [15] programs. The structure model was refined by the Rietveld method employing the JANA2006 program [16].…”

Mechanochemical Synthesis of New Coordination Polymers with Acetylenedicarboxylate as Bridging Ligand

“…It was also attempted to solve the crystal structure of 1 ab initio from powder diffraction data, although the isotypy to SrADC [4] was obvious. Using EXPO2004 [29] a reasonable structural model was obtained in space group I4 1 /a. After transformation into space group I4 1 /amd a structural model very similar to the final crystal structure as given in Table 1 and Figure 2 was obtained.…”

“…15) as possible space groups. The crystal structure of 2 was solved in space group I2/a using EXPO2004 [29]. Only after structural solution it became clear that 2 is isotypic to known compounds of composition [30], Co [7], Ni [9].…”