Structural and magnetic properties of Mn${\mathrm{}\left(\mathrm{SCN}\right)\mathrm{}}_2$${\left({\mathrm{C}}_2{\mathrm{H}}_5\mathrm{O}\mathrm{H}\right)}_2$, a new two-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${\mathrm{}\left(\mathrm{SCN}\right)\mathrm{}}_2$ ${\left({\mathrm{C}}_2{\mathrm{H}}_5\mathrm{O}\mathrm{H}\right)}_2$. The compound belongs to the space group $\frac{P{2}_1}{c}$ with $a=8.535\mathrm{}\left(3\right)\mathrm{}$ Å, $b=6.339\mathrm{}\left(3\right)\mathrm{}$ Å, $c=10.919\mathrm{}\left(4\right)\mathrm{}$ Å, $\beta =94.68\mathrm{}°$, and $z=2\mathrm{}$. 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 $\frac{P{2}_1}{c}$. 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-$\frac{5}{2}$ model with $\frac{J}{k}=-0.88\mathrm{}$ K.