[Infrared spectroscopic determinations of mannitol].

Three different infrared-spectra of Mannit were obtained according to unused Mannit, melted Mannit, and the crystallized form out of methanol. The melting points of the three Mannit-modifications were in accordance 166.5 degrees C. Similar effects have been found with Diethylbarbituric acid. X-ray diffraction patterns and main differences of the infrared-spectra between v = 1100- and 1500 cm-1 - the range, where the molecule in bulk is characterized -, verify three different crystal structures of Mannit.