Antiferromagnetic order in single crystals of theS=2quasi-one-dimensional chainMnCl3(bpy)

The prevailing theme of ``form follows function'' requires structural coherence over sufficient distances to allow subtle magnetic coupling to be revealed in high magnetic field studies at low temperatures. Single-crystal studies of the $S$=2 quasi-one dimensional chain material MnCl${}₃$(2,2'-bipridine) allows the long-range order to be identified, while also revealing the presence of an energy gap at the spin-flop transition field, whose nature remains intriguing.