Investigation of a Smectic Tetramorphous Substance

2-(4-n-pentylphenyl)-5-(4-n-pentyloxyphenyl)-pyrimidine has been prepared. By microscopic investigation, differential scanning calorimetry, dilatometric measurements and X-ray investigation, four different smectic modifications have been stated. The microscopic textures and the relations of miscibility suggest that two of these modifications can be assigned to the group smectic A and C. The other two smectic modifications cannot be assigned to any of the five known groups of smectic modifications. Their characteristics require the establishment of two new groups of smectic modifications with the arbitrary symbol smectic F resp. G.