Structure solution and refinement from powder or single-crystal diffraction data? Pros and cons: An example of the high-pressure Β′-polymorph of glycine

Nikolay Tumanov, Elena V. Boldyreva, Hans Ahsbahs

Research output: Contribution to journalArticle

Abstract

The structure of a high-pressure polymorph of glycine (the Β′ -polymorph formed reversibly at 0.8 GPa from the Β -polymorph) was determined from high-resolution X-ray powder diffraction data collected in situ in a diamond anvil cell at nine pressure points up to 2.6 GPa. X-ray powder diffraction study gave a structural model of at least the same quality as that obtained from a single-crystal diffraction experiment. The difference between the powder-diffraction and the single-crystal models is related to the orientation of the N H3 -tails and the structure of the hydrogen-bonds network. The phase transition between the Β - and Β′ -polymorphs is reversible and preserves a single crystal intact. No transformations were observed between the Β -, α -, and Β′ -polymorphs on compression and decompression, although the α - and Β′ -polymorphs belong to the same space group (P21/c). The instability of the Β - and γ -forms with pressure can be predicted easily when considering the densities of their structures versus pressure. The direction of the transformation (i.e., which of the high-pressure polymorphs is formed) is determined by structural filiation between the parent and the high-pressure phases because of the kinetic control of the transformations.

Original languageEnglish
Pages (from-to)307-316
Number of pages10
JournalPowder Diffraction
Volume23
Issue number4
DOIs
Publication statusPublished - 2008
Externally publishedYes

Keywords

  • Amino acid
  • Grid search technique
  • High pressure
  • Polymorph
  • Simulated annealing
  • Structure solution from powder diffraction data

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  • Datasets

    CCDC 682610: Experimental Crystal Structure Determination

    Ahsbahs, H. (Contributor), Bolldyreva, E. V. (Contributor) & TUMANOV, N. (Contributor), Cambridge Crystallographic Data Centre, 1 Jan 2010

    Dataset

    CCDC 682614: Experimental Crystal Structure Determination

    Ahsbahs, H. (Contributor), Bolldyreva, E. V. (Contributor) & TUMANOV, N. (Contributor), Cambridge Crystallographic Data Centre, 1 Jan 2010

    Dataset

    CCDC 682611: Experimental Crystal Structure Determination

    Ahsbahs, H. (Contributor), Bolldyreva, E. V. (Contributor) & TUMANOV, N. (Contributor), Cambridge Crystallographic Data Centre, 1 Jan 2010

    Dataset

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