Acta Cryst. (2000). B56, 872-881 [ doi:10.1107/S0108768100005905 ]
Abstract: The half-chair conformation of the dynamically disordered molecular ring of 2-methyl-1,3-cyclohexanedione, C
H
O
, transforms to a sofa below 
= 244 K, when the crystal undergoes a continuous phase transition induced by the onset of halting large-amplitude vibrations of methylene groups C(4)H and C(5)H. The temperature dependence of the crystal structure has been investigated by X-ray diffraction. The Ibam symmetry of the crystal reduces below to space group Pccn. The mechanism of the phase transition and of the conversion of the ring conformation is discussed.
Keywords: Conformation; Order-disorder; Phase transitions; Temperature dependence.
Copyright © International Union of Crystallography
IUCr Webmaster