LOW-MELTING POINT ORGANIC-CRYSTAL STRUCTURES BY HIGH-RESOLUTION NEUTRON POWDER DIFFRACTION - THE STRUCTURE DETERMINATION OF ACETALDEHYDE

High-resolution neutron powder diffraction is particularly suited for structure solution and refinement of low melting point organic crystal s. Whereas materials that are gas or liquid at ambient temperature pos e practical difficulties both in growing single crystals and also in p reparing small-volume samples for X-ray studies that exhibit a good po wder average, low-temperature sample preparation and data collection f or neutron powder diffraction experiments is relatively straightforwar d. These practical advantages and high-resolution instrumentation are a powerful combination that enable the precise and accurate determinat ion of moderately complex molecular crystal structures. The structure solution and phase behaviour of acetaldehyde (m.p. 152 K) is described . (C) 1998 Elsevier Science B.V. All rights reserved.