Abstract The molecular structures of N (oC 6 H 4 OH) 3, PhN (oC 6 H 4 OH) 2, and p-TolN (oC 6 H 4 OMe) 2 have been determined by X-ray diffraction, thereby indicating several structural differences. For example, whereas the nitrogen in N (oC 6 H 4 OH) 3 is pyramidal with Σ C–N–C= 348.3∘, the nitrogen atoms in PhN (oC 6 H 4 OH) 2 and p-TolN (oC 6 H 4 OMe) 2 are trigonal planar with Σ C–N–C= 359.9∘ and Σ C–N–C= 360.0∘, respectively. ...