Redetermination of para-amino­pyridine (fampridine, EL-970) at 150 K

The structure of fampridine (EL-970) or 4-amino­pyridine, C₅H₆N₂, has been redetermined at 150 K. The room-temperature structure has been reported previously [Chao & Schempp (1977). Acta Cryst. B33, 1557–1564]. Pyramidalization at the amine N atom occurs in fampridine, with the N atom 0.133 (11) Å from the plane of the three C/H/H atoms to which it is bonded; the inter­planar angle between the pyrid­yl ring and NH₂ group is 21 (2)°. Aggregation in the solid state occurs by N—H...N and N—H...π(pyridine) inter­actions with N...N and N...π(centroid) distances of 2.9829 (18) and 3.3954 (15) Å, respectively; a C—H...π(pyridine) contact completes the inter­molecular inter­actions [C...π(centroid) = 3.6360 (16) Å].