Abstract
The 27Al n.m.r. resonance of the tris-bidentate complex Al(S2CNMe2)3 is unusually narrow and cannot be accounted for by the crystallographic geometry of its structure. The electron density near aluminium cannot therefore coincide with the crystallographic bond directions. It is also proposed that some bond bending occurs in similar complexes of oxoligands, using the ratio of the linewidths of the octahedral and tetrahedral aluminium atoms in the aluminium isopropoxide tetramer as a measure of relative electric-field gradients.