6-O-alpha-D-Galactopyranosyl-D-glucopyranose (melibiose) derivatives w
ith alkyl groups at the terminal 1-O and 6'-O positions have been synt
hesized. They show thermotropic and lyotropic liquid-crystal propertie
s. The d-spacings of the strong inner X-ray diffraction rings correspo
nd to similar to 0.9 times the extended length of the molecule. The mo
lecules are therefore either extended in monomolecular layers or U-sha
ped in bimolecular layers.