AbstractThe crystal unit cell of a series of normal diamides, RNHCO(CH2)2nCONHR (1) with RCH3(CH2)5 andnvarying from 0 up to 4, has been determined from X‐ray diffraction patterns of oriented films. This work forms part of the study to investigate the relation between microstructure and physical properties, in particular diamagnetism. The unit cell is tricline for all members of the series having one chain molecule per unit cell. The structure of normal diamides consists of extended chains tilted 75° from the sheet edge allowing hydrogen‐bond formation within the sheet. The long spacings obtained have been associated to oblique structures of hydrogen‐bonded sheets, except for the diamide withn= 1. A. shear between adjacent hydrogen‐bonded sheets of 3 repeating chain units offers the most probable explanation for the structure