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From space group to space groupoid: the partial symmetry of low-temperature E-vanillyl oxime.

ABSTRACT: The phase transition of E-vanillyl oxime {1-[(E)-(hydroxyimino)methyl]-4-hydroxy-3-methoxybenzene, C8H9NO3} has been analysed by single-crystal and powder X-ray diffraction. The high-temperature (HT) phase (P21/a, Z' = 1) transforms into the low-temperature (LT) phase (threefold superstructure, P\overline{1}, Z' = 6) at ca 190?K. The point operations lost on cooling, {m[010], 2[010]}, are retained as twin operations and constitute the twin law. The screw rotations and glide reflections are retained in the LT phase as partial operations acting on a subset of Euclidean space {\bb E}^3. The full symmetry of the LT phase, including partial operations, is described by a disconnected space groupoid which is built of three connected components.

SUBMITTER: Ehrmann K

PROVIDER: S-EPMC6690132 | biostudies-literature | 2019 Aug

REPOSITORIES: biostudies-literature

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From space group to space groupoid: the partial symmetry of low-temperature E-vanillyl oxime.

Ehrmann Katharina K Baudis Stefan S Stöger Berthold B

Acta crystallographica Section B, Structural science, crystal engineering and materials 20190723 Pt 4

The phase transition of E-vanillyl oxime {1-[(E)-(hydroxyimino)methyl]-4-hydroxy-3-methoxybenzene, C8H9NO3} has been analysed by single-crystal and powder X-ray diffraction. The high-temperature (HT) phase (P21/a, Z' = 1) transforms into the low-temperature (LT) phase (threefold superstructure, P\overline{1}, Z' = 6) at ca 190 K. The point operations lost on cooling, {m[010], 2[010]}, are retained as twin operations and constitute ...[more]

PMID: 32830729

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