The crystal structure of methanol monohydrate (CD3OD · D2O) at 160 K from powder neutron diffraction

The structure of methanol monohydrate at 160 K has been solved from powder neutron diffraction data by ab initio methods. The crystal is orthorhombic, space-group Cmc21 (Z = 4) with unit cell dimensions a = 4.64910(2) Å, b = 14.08464(7) Å, c = 4.69358(1) Å, V = 307.340(2) Å3 (ρcalc = 1212.29(1) kg m−3) at 160 K. The structure consists of water–water chains, linked by ordered hydrogen bonds extending along the c-axis, which cross link methanol–water chains with disordered hydrogen bonds along the a-axis. These perpendicular chains form sheets which are stacked parallel to the b-axis.