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Using phases retrieved from two-dimensional projections to facilitate structure solution from X-ray powder diffraction data

J. Appl. Cryst. (2011). 44, 1023-1032 (

[Density map]

The electron-density map at the right was produced from a two-dimensional subset of reflections extracted from a powder diffraction pattern (dmin=1.5 Å). For comparison, an HRTEM image of the projection has been overlaid (upper right), and the projected unit cell of the zeolite framework structure (IM-5) superimposed (upper left). It has been found that by applying the charge-flipping structure solution algorithm to such low-resolution two-dimensional subsets of reflections, more correct phases are obtained than when the full dataset is used. By combining a few such subsets, a set of starting phases can be generated, allowing previously inaccessible structures to be solved from the powder diffraction data alone.

D. Xie, Ch. Baerlocher and L. B. McCusker