  The magnetic ordering of superconducting single crystals of
K_0.85Fe_1.83Se_2.09 has been studied between 10K and 550K using 57-Fe
Mossbauer spectroscopy. Despite being superconducting below T_sc ~30K, the iron
sublattice in K_0.85Fe_1.83Se_2.09 clearly exhibits magnetic order from well
below T_sc to its N\'eel temperature of T_N = 532 +/- 2K. The iron moments are
ordered perpendicular to the single crystal plates, i.e. parallel to the
crystal c-axis. The order collapses rapidly above 500K and the accompanying
growth of a paramagnetic component suggests that the magnetic transition may be
first order, which may explain the unusual temperature dependence reported in
recent neutron diffraction studies.
