  Antiferromagnetic order at $T_{\mathrm{N}} = 23$ K has been identified in
Mn(III)F(salen), salen = H$_{14}$C$_{16}$N$_2$O$_2$, an $S = 2$ linear-chain
system. Using single crystals, specific heat studies performed in magnetic
fields up to 9 T revealed the presence of a field-independent cusp at the same
temperature where $^1$H NMR studies conducted at 42 MHz observed dramatic
changes in the spin-lattice relaxation time, $T_1$, and in the linewidths.
Neutron powder diffraction performed on a randomly-oriented, as-grown,
deuterated (12 of 14 H replaced by d) sample of 2.2 g at 10 K and 100 K did not
resolve the magnetic ordering, while low-field (less than 0.1 T) magnetic
susceptibility studies of single crystals and randomly-arranged
microcrystalline samples reveal subtle features associated with the transition.
Ensemble these data suggest a magnetic signature previously detected at 3.8 T
for temperatures below nominally 500 mK is a spin-flop field of small net
moments arising from alternating subsets of three Mn spins along the chains.
