Acta Crystallographica Section B

Structural Science

Volume 61, Part 4 (August 2005)

research papers

Acta Cryst. (2005). B61, 449-454 [ doi:10.1107/S0108768105019191 ]

The low-temperature and high-pressure crystal structures of cyclobutanol (C₄H₇OH)

P. A. McGregor, D. R. Allan, S. Parsons and C. R. Pulham

Abstract: The low-temperature and high-pressure crystal structures of cyclobutanol (C₄H₇OH) have been determined using single-crystal X-ray diffraction techniques. At temperatures below 220 K, cyclobutanol crystallizes in the Aba2 space group (Z' = 2) and its crystal structure is composed of pseudo-threefold hydrogen-bonded molecular catemers [assigned as in graph-set notation], which lie parallel to the crystallographic a axis. At a pressure of 1.3 GPa, the crystal symmetry changes to Pna2₁ (Z' = 1) and the molecular catemers [expressed as C(2) in graph-set notation] adopt a pseudo-twofold arrangement. This structural behaviour is in agreement with our previous observations for phenol and its halogenated derivatives 2-chlorophenol and 4-fluorophenol, where pressure was found to favour a molecular packing more closely associated with small alkyl groups rather than that of relatively bulky alkyl groups. In addition, an examination of the molecular coordination environment in the low-temperature and high-pressure structures of cyclobutanol reveals that the change in structure on application of pressure appears to be driven by the molecules assuming a packing arrangement which more closely resembles that adopted in hard-sphere structures.

Keywords: low-temperature and high-pressure structure; X-ray diffraction; graph-set notation; molecular packing.


	Structure factor file (CIF format) (133.3 kbytes) Contains datablock cb220K

	Structure factor file (CIF format) (155.0 kbytes) Contains datablock cb100K

	Structure factor file (CIF format) (25.7 kbytes) Contains datablock cbutan

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