STRUCTURAL AND DYNAMICAL ASPECTS OF SOLID SULPHOLAN IN THE TEMPERATURE-RANGE 160-300 K .1. X-RAY-POWDER DIFFRACTION STUDY

The X-ray diffraction study of polycrystalline sulpholan has been carr ied out in the T = 200-300 K temperature range, in order to compare wi th previous NMR results about the existence of two high-temperature ph ases I and II and of two low-temperature phases III and IV. The transi tion I-II could be evidenced by the temperature evolution of the relat ive intensities of the observed diffraction lines. The crystalline pha ses III and IV were identified as monoclinic, with a = 12.29(1) Angstr om b = 10.23(1) Angstrom, c = 9.27(1) Angstrom, beta = 97.49(5)degrees , space group P2(1)/c, Z = 8 at T = 230 K. The transition III-IV was o bserved only as a discontinuity in the temperature evolution of lattic e parameters.