2-Acetamido-3-0-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-a-D-galactopyranosyl)-l,4,6-tri-O-acety1-2-deoxy-a-D-galactopyranose (1) crystallizes in the orthorhombic space group P2,2i2i with four molecules of disaccharide and six water molecules in the unit cell. Both of the N-acetyl groups are disordered. The conformation of 1 in solution was estimated by 'H-n.m.r. spectroscopy of NOE effects. A comparison of the linkage torsion-angles shows that, in solution, the conformation of 1 at the glycosidic linkage is very similar to that in the crystalline state. By neglecting the 0-acetyl groups, the conformation of 1 could be obtained by HSEA calculation. ZUSAMMENFASSUNG 2-Acetamido-3-0-(2-acetamido-3,4,6-tri-O-acetyl-2-desoxy-cu-D-galactopyranosyl)-l,4,6-tri-O-acety1-2-desoxy-cu-D-galactopyranose kristallisiert orthorhombisch (P2,2,2r) mit vier Disaccharidmolektilen und sechs Wassermolektilen in der Elementarzelle. Die Fehlordnungen der N-Acetylgruppen und die Wasserstoffbrtickenbindungen werden diskutiert. Zur Bestimmung der Konformation von 1 in Losung wird eine 'H-N.m.r.-spektroskopische IJntersuchung der NOE-'Abk. NOE, Nuclear Overhauser Effect (Nuklear Overhauser-Verstlrkung); HSEA, Hard-sphere Calculation. +Xx111. Mitteilung der Serie Konformationsanalyse XXII. Mitteil., s. Zil. 1.