STRUCTURAL AND MAGNETIC-PROPERTIES OF MN(SCN)2(C2H5OH)2, A NEW 2-DIMENSIONAL HEISENBERG MAGNET

The room-temperature crystal structure as well as low-temperature magnetic studies which include heat-capacity, proton-resonance, and magnetic-susceptibility experiments are reported for Mn(SCN)2(C2H5OH)2. The compound belongs to the space group P21c with a=8.535(3), b=6.339(3)c=10.919(4), β=94.68°, and z=2. The structure consists of polymeric sheets of thiocynate-bridged manganese ions with the sheets being separated by the ethanol groups, which are coordinated to the manganese ions. The compound magnetically orders at 10.30±0.01 K with the magnetic space group being P21c. In the ordered state the Mn spins lie within the polymeric sheets and are canted such as to give a net magnetization along the b axis. In zero-field domain effects result in essentially equal volumes of crystal with net magnetizations along the positive and negative b axis. In the paramagnetic region the susceptibility and heat-capacity results are reasonably well described by the two-dimensional square-planar Heisenberg spin-52 model with Jk=-0.88 K. © 1979 The American Physical Society.